JP2017037005A - Lift and drag measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel lift drag measurement device capable of measuring lift and drag which act on a model in a wind tunnel test without using electronic equipment.SOLUTION: A lift drag measurement device for measuring lift and drag which act on a model in a wind tunnel comprises: a disk-shaped rotary pedestal to which the model can be attached, in an eccentric position; a rotary shaft which is fixed to a center of a rear surface of the rotary pedestal; rotary shaft support means for pivotally supporting the rotary shaft and which is fixed to a wall surface of the wind tunnel; first rotary torque application means for applying a rotary torque which balances a rotary torque which is applied to the rotary shaft by gravity acting on the model, to the rotary shaft; second rotary torque application means for applying a rotary torque which balances a rotary torque which is applied to the rotary shaft by lift and drag which act on the model, to the rotary shaft; and balance state presentation means for presenting a balance state of the rotary torque.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a lift / drag force measuring apparatus, and more particularly to an apparatus for measuring lift / drag acting on a model in a wind tunnel experiment without using an electronic device.

  Conventionally, a device for measuring lift and drag acting on a model in a wind tunnel experiment has to be equipped with some electronic device (for example, Patent Document 1).

JP 2008-249527 A

  The present invention has been made in view of the above problems in the prior art, and the present invention provides a novel lift / drag force measuring device for measuring lift / drag acting on a model in a wind tunnel experiment without using an electronic device. The purpose is to provide.

  As a result of intensive studies on a configuration for measuring lift and drag acting on a model in a wind tunnel experiment without using an electronic device, the present inventor has conceived the following configuration and arrived at the present invention.

  That is, according to the present invention, a lift / drag force measuring device for measuring a lift / drag force acting on a model in a wind tunnel, a disc-shaped rotary pedestal capable of attaching the model to an eccentric position, and a back surface of the rotary pedestal A rotating shaft fixed to the center of the wind tunnel, a rotating shaft support means fixed to the wall of the wind tunnel and supporting the rotating shaft, and a rotating torque that balances with the rotating torque applied to the rotating shaft by gravity acting on the model. A first rotational torque applying means for applying to the rotating shaft; and a second rotating torque for applying to the rotating shaft a rotational torque that balances the rotational torque applied to the rotating shaft by the lifting force acting on the model. There is provided a lift / drag force measuring device including an applying unit and a balance state presenting unit for presenting a balance state of the rotational torque.

  As described above, according to the present invention, there is provided a novel lift / drag force measuring device for measuring lift / drag acting on a model in a wind tunnel experiment without using an electronic device.

The figure which shows the vertical wind tunnel apparatus with which the lift force measuring apparatus of this embodiment was attached. The perspective view of the lift / drag force measuring apparatus of this embodiment. The figure which shows the rotation base in this embodiment. The schematic diagram for demonstrating the method of setting an angle of attack. The schematic diagram for demonstrating the aerodynamic force (lift force / drag) which acts on a wing | blade. The schematic diagram for demonstrating position alignment of a rotation base. The figure which shows four types of reference | standard states. The schematic diagram for demonstrating the setting procedure of reference | standard states (1) and (2). The schematic diagram for demonstrating the setting procedure of reference | standard states (1) and (2). The schematic diagram for demonstrating the experimental procedure under a reference | standard state (1). The schematic diagram for demonstrating the experimental procedure under a reference | standard state (2). The schematic diagram for demonstrating the setting procedure of the reference | standard states (3) and (4). The schematic diagram for demonstrating the setting procedure of the reference | standard states (3) and (4). The schematic diagram for demonstrating the experimental procedure under a reference | standard state (3). The schematic diagram for demonstrating the experimental procedure under a reference | standard state (4). The schematic diagram for demonstrating the lift L and the drag D which act on a rotation base under reference | standard states (1)-(4). The figure which shows the disc for position alignment. The graph which shows an experimental result.

  Hereinafter, the present invention will be described with reference to embodiments shown in the drawings, but the present invention is not limited to the embodiments shown in the drawings. In the drawings referred to below, the same reference numerals are used for common elements, and the description thereof is omitted as appropriate.

  FIG. 1 shows a vertical wind tunnel device 200 to which a lifting force measuring device 100 according to an embodiment of the present invention is attached. The vertical wind tunnel device 200 includes a first rectifying unit 92, a contracted portion 93, a wind tunnel 94 formed of a transparent cylindrical member, a second rectifying unit 95, an intake fan 97, and a pedestal 98. The air rectified by the first rectifying unit 92 is introduced into the wind tunnel 94 through the contracted flow unit 93 and flows downward in the vertical direction by driving the intake fan 97. With respect to the vertical wind tunnel device 200, the lift / drag force measuring device 100 of the present embodiment is fixed so as to straddle the wall surface of the wind tunnel 94.

  FIG. 2 is a perspective view of the lift / drag force measuring apparatus 100. As shown in FIG. 2, the lift / drag force measuring apparatus 100 includes a disc-shaped rotary base 10, a rotary shaft 20 fixed to the rotary base 10, and a rotary shaft support that supports the rotary shaft 20 with a bearing having a small frictional resistance. In order to present the balance state of the rotational torque applied to the rotating shaft 20, the first rotating torque applying means 40 and the second rotating torque applying means 50 for applying the rotating torque to the rotating shaft 20. The balance state presenting means 60 is configured.

  The rotary shaft support means 30 is fixed to the wall surface of the wind tunnel 94, and its bearing rotatably supports the rotary shaft 20 in a form orthogonal to the longitudinal direction of the wind tunnel 94. A part of the rotary shaft 20 supported by the rotary shaft support means 30 protrudes inside the wind tunnel 94 and the remaining part protrudes outside the wind tunnel 94.

  On the other hand, the rotary pedestal 10 is detachably fixed to the end of the rotary shaft 20 protruding inside the wind tunnel 94. 3A shows the surface of the rotary pedestal 10, and FIGS. 3B and 3C are cross-sectional views taken along the line A-A 'of the rotary pedestal 10. FIG. As shown in FIG. 3, the rotary pedestal 10 includes a large disk 12 and a small disk 14, and as shown in FIGS. 3B and 3C, at the center of the back surface of the large disk 12, A fitting portion 19 having a hole for fitting the end portion is formed.

  The large disk 12 and the small disk 14 have the same thickness, and the rotating base 10 is configured by fitting and integrating the small disk 14 with a circular opening 13 formed in the large disk 12. The opening 13 formed in the large disk 12 has its center at a position eccentric from the rotation center of the rotary base 10 so that the diameter of the opening 13 gradually increases from the front surface to the back surface of the large disk 12. The inner peripheral side surface is tapered. On the other hand, the outer peripheral side surface of the small disk 14 is formed in a tapered shape so as to match the inner peripheral side surface of the opening 13, and the surface of the rotary base 10 is a surface when the small disk 14 is fitted to the large disk 12. It is configured to be one.

  Here, on the surface of the small disk 14, two protrusions 16 a and 16 b for mounting the model wing 80 to be measured are arranged in parallel in the diameter direction, and the small disk 14 is fitted to the large disk 12. Then, the protrusions 16a and 16b protrude from the surface of the rotary base 10. On the other hand, two holes 82a and 82b having shapes and sizes corresponding to the protrusions 16a and 16b are arranged side by side in the blade chord direction on the side surface of the blade 80, and the protrusions 16a and 16b are formed in the holes 82a and 82b. By fitting, the wing 80 is attached to the eccentric position of the rotary base 10 so that the chord direction thereof coincides with the diameter direction of the small disk 14.

  Further, in the present embodiment, a mark 17 indicating the chord direction of the blade 80 is displayed on the surface of the small disk 14, and a scale 18 indicating the angle over the entire circumference of the edge of the opening 13 to which the small disk 14 is fitted. Are engraved at equal intervals (for example, every 5 degrees). In the present embodiment, as shown in FIG. 3C, using the scale 18 as a guide, the small disk 14 is rotated in the circumferential direction and fitted to the large disk 12, so that FIG. , (B), the angle of attack θ of the blade 80 can be set to a desired angle.

  Furthermore, in this embodiment, in order to set four types of reference states to be described later, a large scale is respectively provided for each of the two scales 18 positioned on a straight line passing through the center of the large disk 12 and the center of the small disk 14. A mark “2” and a mark “1” are given in order from the center of the disk 12, and a mark “4” is placed on the scale 18 at a position 90 ° clockwise from the mark “2”. ”And the scale 18 at a position 90 ° clockwise from the mark“ 1 ”is marked with a mark“ 3 ”.

  Returning again to FIG. 2, the description will be continued.

  As shown in FIG. 2, the rotating shaft 20 that protrudes outside the wind tunnel 94 includes, in order from the wind tunnel 94, a first rotating torque applying means 40, a second rotating torque applying means 50, and a balance. A state presentation means 60 is attached.

  First, the first rotational torque applying means 40 will be described. The first rotational torque applying means 40 is orthogonal to the rotary shaft 20 at a position opposite to the outer peripheral side surface of the shaft fixing means 42 and a ring-shaped shaft fixing means 42 that is rotatably fixed to the rotary shaft 20. A pair of shafts 44, 44 fixed in shape and a ring-shaped weight 48 fitted to the shaft 44 are included. In the present embodiment, the rotational torque due to gravity acting on the blade 80 attached to the eccentric position of the rotary base 10 acts on the rotary shaft 20. On the other hand, the rotational torque due to the gravity of the weight 48 fixed to the shaft 44 acts so as to cancel the rotational torque due to the gravity of the blade 80.

  Here, the weight 48 can be freely changed in its fixed position by sliding in the axial direction of the shaft 44, whereby the magnitude of the rotational torque applied to the rotary shaft 20. Can be adjusted. Further, the shaft fixing means 42 is configured to be able to freely change the fixing position around the axis by rotating around the axis of the rotary shaft 20.

  Next, the second rotational torque applying means 50 will be described. The second rotational torque applying means 50 is a pair of cylinder-shaped shaft fixing means 52 fixed to the rotating shaft 20 and a pair of shafts fixed so that the center of the shaft coincides with the opposing position of the outer peripheral side surface of the shaft fixing means 52. , And a ring-shaped weight 58 fitted to the shaft 54.

  In the present embodiment, when the air flows vertically toward the wing 80 fixed to the rotating base 10 in the wind tunnel 94, an aerodynamic force A acts on the wing 80 as shown in FIG. The vertical component of the aerodynamic force A is considered as the drag D, and the horizontal component is considered as the lift L. In the present embodiment, as described above, the wing 80 is attached to the eccentric position of the rotary base 10, so that the rotational torque due to the aerodynamic force A acting on the wing 80 acts on the rotary shaft 20. On the other hand, the rotational torque due to the gravity of the weight 58 fixed to the shaft 54 acts to cancel the rotational torque due to the aerodynamic force A acting on the blade 80.

  Here, the weight 58 can be freely changed in its fixed position by sliding in the axial direction of the shaft 54, whereby the magnitude of the rotational torque applied to the rotary shaft 20. Can be adjusted. Further, the shaft fixing means 52 can rotate freely around the axis of the rotary shaft 20 to freely change the fixed position around the axis. Further, in the axial direction of the shaft 54, a scale 56 for reading a separation distance between the central axis of the rotating shaft 20 and the center of gravity of the weight 58 is engraved.

  Next, the balance state presentation unit 60 will be described. The balance state presentation means 60 includes a bearing 62 having a small frictional resistance that is rotatably fitted to the rotary shaft 20, a string 64 fixed to the outer peripheral surface of the bearing 62, and a weight fixed to the end of the string 64. 66 and an alignment disc 68 in which the end of the rotating shaft 20 is fixed to the center thereof. Here, the outer peripheral surface of the bearing 62 having a small frictional resistance is not rotated around the shaft against the rotation of the rotary shaft 20, and the longitudinal direction of the string 64 suspended from the bearing 62 is always vertical. It matches the direction. On the other hand, the alignment disc 68 is formed of a transparent material, and as shown in FIG. 6, a circle is provided on the surface thereof as an index for performing alignment with respect to the vertical direction presented by the string 64. A reference line R extending in the diameter direction through the center of the plate is displayed.

  Further, in the present embodiment, as shown in FIG. 6, alignment protrusions are formed on the end portions of the rotating shaft 20 fixed to the rotating base 10. The ridges are formed in the cross direction of the rotary shaft 20 so that the vertical direction of the cross is parallel to the reference line R displayed on the alignment disc 68. On the other hand, in the hole of the fitting portion 19 of the rotating base 10, an alignment groove corresponding to the alignment protrusion of the rotating shaft 20 is formed in the cross direction of the hole. Further, the pair of shafts 54 of the second rotational torque applying means 50 are fixed to the shaft fixing means 52 so as to be parallel to the direction orthogonal to the reference line R.

  The configuration of the lift / drag force measuring apparatus 100 has been described above. Next, a method for measuring the lift / drag force using the lift / drag force measuring apparatus 100 will be described.

  In the present embodiment, when the lift / drag force is measured using the lift / drag force measuring apparatus 100, a maximum of 4 wind tunnel experiments are performed for one measurement object. In each experiment, the rotating pedestal 10 is placed in four different reference states. FIGS. 7A to 7D show four different reference states.

  In the reference state (1), as shown in FIG. 7A, the small disk 14 is positioned vertically upward as viewed from the center of the large disk 12, and the leading edge of the wing 80 fixed to the small disk 14 is A state in which a straight line S1 that faces upward in the vertical direction and passes through the center of the small disk 14 and the center of the large disk 12 (hereinafter referred to as a straight line S1) coincides with the vertical direction V.

  In the reference state (2), as shown in FIG. 7B, the small disk 14 is positioned vertically downward as viewed from the center of the large disk 12, and the leading edge of the wing 80 fixed to the small disk 14 is It refers to a state in which the vertical direction is upward and the straight line S1 coincides with the vertical direction V.

  In the reference state (3), as shown in FIG. 7C, the small disk 14 is located on the left side of the paper as viewed from the center of the large disk 12, and the leading edge of the wing 80 fixed to the small disk 14 is vertical. A state in which the straight line S <b> 1 coincides with the horizontal direction H with the direction upward.

  In the reference state (4), as shown in FIG. 7 (d), the small disk 14 is located on the right side of the paper as viewed from the center of the large disk 12, and the leading edge of the wing 80 fixed to the small disk 14 is vertical. A state in which the straight line S <b> 1 coincides with the horizontal direction H with the direction upward.

  Subsequently, specific procedures of the wind tunnel experiment will be described for each reference state. In each experiment, the conditions of the airflow velocity and the angle of attack of the blade 80 are unified.

  First, the rotating pedestal 10 is placed in the reference state (1). Specifically, first, the small disk 14 is fitted to the rotating pedestal 10 so that the blade 80 takes the angle of attack θ determined with reference to the mark “1”. Thereafter, the rotary pedestal 10 to which the blades 80 are attached is inserted into the wind tunnel 94, and the end of the rotary shaft 20 is fitted and fixed to the back surface of the rotary pedestal 10. At this time, as shown in FIG. 8A, the rotation is performed with respect to the alignment groove of the rotation base 10 so that the straight line S1 of the rotation base 10 and the reference line R of the alignment disk 68 are parallel to each other. A protrusion for positioning the shaft 20 is fitted.

  Subsequently, as shown in FIG. 8B, the shaft fixing means 42 of the rotary shaft 20 is set so that the straight line S1 of the rotary base 10 and the axial direction of the shaft 44 of the first rotational torque applying means 40 are substantially parallel. After rotating around the axis, the weight 48 is fitted to the axis 44 that does not face the small disk 14. Thereafter, until the alignment disc 68 comes to rest when the hand is released at an arbitrary angle, as shown in FIG. 9A, the shaft fixing means 42 (the shaft 44) is rotated around the axis of the rotary shaft 20. And the position in the axial direction of the shaft 44 of the weight 48 are finely adjusted. In other words, the axial direction of the shaft 44 and the straight line connecting the rotation center of the rotary pedestal 10 and the center of gravity of the rotary pedestal 10 are parallel, and the rotational torque due to the gravity of the weight 48 and the rotational torque due to the gravity of the blade 80 are balanced. Until this happens, the angle of the shaft fixing means 42 (the shaft 44) and the position of the weight 48 are finely adjusted by trial and error. (The same applies to the reference states (2) to (3) below.)

  Finally, as shown in FIG. 9B, the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 are matched. As a result, the rotating pedestal 10 is placed in the reference state (1) shown in FIG.

  With the rotary pedestal 10 placed in the reference state (1), airflow is generated in the wind tunnel 94 with the hand gently attached so that the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 do not shift. When introduced, as shown in FIG. 10B, an aerodynamic force acts on the wings 80 attached to the rotating base 10, and a rotational torque T1 due to this aerodynamic force acts on the rotating shaft 20 to cause the rotating shaft 20 to move to the sheet clock. Try to rotate around.

  In response, after the weight 58 is fitted to the shaft 54 on the left side of the drawing, the axial position of the shaft 54 of the weight 58 is maintained until the reference state (1) is maintained even if the hand is released. Make fine adjustments on a trial and error basis. As a result, as shown in FIG. 10C, when the reference state (1) is maintained even if the hand is released, the scale 56 carved on the shaft 54 is read, and the rotation shaft 20 A distance d1 between the center axis and the center of gravity of the weight 58 is acquired.

  Subsequently, the rotating pedestal 10 is placed in the reference state (2). Specifically, first, the small disk 14 is fitted to the rotating pedestal 10 so that the wing 80 takes the angle of attack θ determined with reference to the mark “2”. Thereafter, the rotary pedestal 10 to which the blades 80 are attached is inserted into the wind tunnel 94, and the end of the rotary shaft 20 is fitted and fixed to the back surface of the rotary pedestal 10.

  At this time, as in the reference state (1), the alignment groove of the rotary pedestal 10 is aligned with the straight line S1 of the rotary pedestal 10 and the reference line R of the alignment disc 68 in parallel. The shaft fixing means 42 is rotated so that the alignment protrusion of the rotary shaft 20 is fitted and the straight line S1 of the rotary base 10 and the axial direction of the shaft 44 of the first rotational torque applying means 40 are substantially parallel. After rotating around the axis of the axis 20, the weight 48 is fitted to the axis 44 that does not face the small disk 14.

  Thereafter, the position of the shaft fixing means 42 (the shaft 44) around the axis of the rotary shaft 20 and the axis of the shaft 44 of the weight 48 until the positioning disc 68 comes to rest when the hand is released at an arbitrary angle. After finely adjusting the position of the direction by trial and error, the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 are matched. As a result, the rotating pedestal 10 is placed in the reference state (2) shown in FIG.

  With the rotary pedestal 10 placed in the reference state (2), airflow is passed into the wind tunnel 94 with the hand gently attached so that the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 do not deviate. When introduced, as shown in FIG. 11B, an aerodynamic force acts on the wings 80 attached to the rotating base 10, and a rotational torque T2 due to this aerodynamic force acts on the rotating shaft 20 to cause the rotating shaft 20 to move away from the page. Try to rotate clockwise.

  In response to this, after the weight 58 is fitted to the shaft 54 on the left side of the page, the axial position of the shaft 58 of the weight 58 is maintained until the reference state (2) is maintained even if the hand is released. Make fine adjustments on a trial and error basis. As a result, as shown in FIG. 11C, when the reference state (2) is maintained even when the hand is released, the scale 56 carved on the shaft 54 is read, and the rotation shaft 20 A distance d2 between the center axis and the center of gravity of the weight 58 is acquired.

  Subsequently, the rotary base 10 is placed in the reference state (3). Specifically, first, the small disk 14 is fitted to the rotating pedestal 10 so that the wing 80 takes an angle of attack θ determined with reference to the mark “3”. Thereafter, the rotary pedestal 10 to which the blades 80 are attached is inserted into the wind tunnel 94, and the end of the rotary shaft 20 is fitted and fixed to the back surface of the rotary pedestal 10. At this time, as shown in FIG. 12A, a straight line S2 (hereinafter referred to as a straight line S2) that passes through the center of the rotating base 10 and is orthogonal to the straight line S1 is parallel to the reference line R of the alignment disc 68. As described above, the alignment protrusion of the rotary shaft 20 is fitted into the alignment groove of the rotary base 10.

  Subsequently, as shown in FIG. 12B, the shaft fixing means 42 of the rotary shaft 20 is set so that the straight line S1 of the rotary base 10 and the axial direction of the shaft 44 of the first rotational torque applying means 40 are substantially parallel. After rotating around the axis, the weight 48 is fitted to the axis 44 that does not face the small disk 14. Thereafter, until the alignment disc 68 comes to rest when the hand is released at an arbitrary angle, as shown in FIG. 13A, the shaft fixing means 42 (the shaft 44) is rotated around the axis of the rotary shaft 20 as shown in FIG. And the position in the axial direction of the shaft 44 of the weight 48 are finely adjusted.

  Finally, as shown in FIG. 13B, the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 are matched. As a result, the rotating pedestal 10 is placed in the reference state (3) shown in FIG.

  With the rotary pedestal 10 placed in the reference state (3), airflow is passed into the wind tunnel 94 with the hand gently attached so that the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 do not deviate. When introduced, as shown in FIG. 14B, an aerodynamic force acts on the wings 80 attached to the rotary base 10, and the rotational torque T3 due to this aerodynamic force acts on the rotary shaft 20 to cause the rotary shaft 20 to move away from the paper surface. Try to rotate clockwise.

  In response to this, after the weight 58 is fitted to the shaft 54 on the left side of the page, the axial position of the shaft 58 of the weight 58 is maintained until the reference state (3) is maintained even if the hand is released. Make fine adjustments on a trial and error basis. As a result, as shown in FIG. 14C, when the reference state (3) is maintained even when the hand is released, the scale 56 carved on the shaft 54 is read, and the rotation shaft 20 A distance d3 between the center axis and the center of gravity of the weight 58 is acquired.

  Subsequently, the rotating pedestal 10 is placed in the reference state (4). Specifically, first, the small disk 14 is fitted to the rotary pedestal 10 so that the blade 80 takes an angle of attack θ determined with reference to the mark “4”. Thereafter, the rotary pedestal 10 to which the blades 80 are attached is inserted into the wind tunnel 94, and the end of the rotary shaft 20 is fitted and fixed to the back surface of the rotary pedestal 10. At this time, as in the reference state (3), the alignment groove of the rotary pedestal 10 is aligned with the straight line S2 of the rotary pedestal 10 and the reference line R of the alignment disc 68 in parallel. The shaft fixing means 42 is rotated so that the alignment protrusion of the rotary shaft 20 is fitted and the straight line S1 of the rotary base 10 and the axial direction of the shaft 44 of the first rotational torque applying means 40 are substantially parallel. After rotating around the axis of the axis 20, the weight 48 is fitted to the axis 44 that does not face the small disk 14.

  Thereafter, the position of the shaft fixing means 42 (the shaft 44) around the axis of the rotary shaft 20 and the axis of the shaft 44 of the weight 48 until the positioning disc 68 comes to rest when the hand is released at an arbitrary angle. After finely adjusting the position of the direction by trial and error, the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 are matched. As a result, the rotary pedestal 10 is placed in the reference state (4) shown in FIG.

  With the rotary pedestal 10 placed in the reference state (4), airflow is passed into the wind tunnel 94 with the hand gently attached so that the reference line R of the alignment disc 68 and the vertical direction presented by the string 64 do not shift. When introduced, as shown in FIG. 15B, an aerodynamic force acts on the wings 80 attached to the rotating base 10, and a rotational torque T4 due to this aerodynamic force acts on the rotating shaft 20 to cause the rotating shaft 20 to move to the sheet clock. Try to rotate around.

  In response, after the weight 58 is fitted to the shaft 54 on the left side of the page, the axial position of the shaft 54 of the weight 58 is maintained until the reference state (4) is maintained even if the hand is released. Make fine adjustments on a trial and error basis. As a result, as shown in FIG. 15C, when the reference state (4) is maintained even if the hand is released, the scale 56 carved on the shaft 54 is read, and the rotation shaft 20 A distance d4 between the center axis and the center of gravity of the weight 58 is acquired.

  The procedure of the wind tunnel experiment performed up to four times for one measurement object has been described above. Next, the procedure for calculating the lift / drag force using the result of the wind tunnel experiment described above will be described.

  FIG. 16 shows the aerodynamic forces (lift L and drag D) acting on the rotating pedestal 10 and their actions when the rotating pedestal 10 is placed in the reference states (1) to (4) and the airflow is caused to flow down in the vertical direction V. Indicates a point. Here, the relationship between the lift L and the drag D in the reference states (1) to (4) can be expressed by the following formulas (1) to (4), respectively.

  In the above formulas (1) to (4), η represents the horizontal distance between the center of the small disk 14 and the point of action of the aerodynamic force A, and ξ represents the center of the small disk 14 and the point of action of the aerodynamic force A. , R represents the distance between the center of the large disk 12 and the center of the small disk 14, and T1 to T4 represent the rotational torque that the aerodynamic force A brings to the rotating shaft 20.

  Here, T1 to T4 in the above formulas (1) to (4) are the separation distances d1 to d4 acquired in the wind tunnel experiment performed with the rotating base 10 placed in the reference state (1) to (4), and the weight It is obtained by substituting the mass m of 58 and the gravitational acceleration g into the following formulas (5) to (8).

  In the present embodiment, the lift L can be calculated as a solution of the simultaneous equations consisting of the above equations (1) and (2), and the drag D as a solution of the simultaneous equations consisting of the above equations (3) and (4). Can be calculated. Further, the lift L and the drag D are calculated as solutions of the simultaneous equations consisting of the above formulas (1), (2), (3) or the simultaneous equations consisting of the above formulas (1), (2), (4). Can do. In addition, lift L and drag D are calculated as solutions of simultaneous equations consisting of the above equations (1), (3) and (4) or simultaneous equations consisting of the above equations (2), (3) and (4). can do.

  That is, in this embodiment, when only the lift L is measured, two wind tunnel experiments may be performed with the rotating base 10 in two reference states (1) and (2), and only the drag D is measured. The two wind tunnel experiments may be performed with the rotating base 10 in two reference states (3) and (4). When both lift L and drag D are measured, the wind tunnel experiment may be performed on any one of the three reference states selected from the four reference states (1) to (4).

  As described above, according to the lift / drag force measuring apparatus 100 of the present embodiment, the lift / drag acting on the model in the wind tunnel experiment can be measured without using an electronic device.

  As mentioned above, although this invention was demonstrated with embodiment, this invention is not limited to embodiment mentioned above, A various design change is possible.

  For example, the index for alignment displayed on the surface of the alignment disk 68 of the balance state presentation means 60 is not limited to the reference line R described above, and alignment with respect to the vertical direction presented by the string 64 is performed. As long as it is possible, the indicator of any aspect may be used. FIG. 17 exemplifies a positioning disc 68 in which a scale of a protractor is engraved as a positioning index. The alignment disc 68 may not be transparent.

  Further, in the above-described embodiment, the configuration in which the alignment groove and the hole are formed in each of the rotating shaft 20 and the fitting portion 19 of the rotating pedestal 10 is shown, but instead, on the back surface of the rotating pedestal 10. Adopting a configuration in which at least one of the fixed position around the rotation axis 20 of the rotating base 10 and the fixed position around the rotation axis 20 of the alignment disc 68 can be changed after displaying the straight line S1 and the straight line S2. Also good. In this case, it is visually confirmed that the reference line R of the alignment disc 68 and the straight line S1 or the straight line S2 of the back surface of the rotary pedestal 10 are parallel, and the rotation axis of the rotary pedestal 10 or the alignment disc 68 is confirmed. A fixed position around 20 is determined.

  In the above-described embodiment, an example in which the lift / drag force measuring device 100 is attached to the vertical wind tunnel device has been described. However, the lift / drag force measuring device 100 according to the present embodiment is not limited to a vertical flow wind tunnel but also a horizontal flow. Needless to say, it also functions effectively in the wind tunnel. In addition, within the scope of other embodiments that can be considered by those skilled in the art, the present invention is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited.

  Hereinafter, although the lift / drag force measuring apparatus of the present invention will be described more specifically with reference to examples, the present invention is not limited to the examples described later.

  A lift / drag force measurement device similar to that shown in FIG. 2 was produced, and the produced lift / drag force measurement device was set in a vertical cylindrical suction type wind tunnel. And the wind tunnel experiment which put the disk pedestal in the reference | standard state (1) mentioned above, (2), (3) was conducted, and the lift L and the drag D were calculated | required by calculation based on the experimental result. The experiment was conducted by setting the maximum flow velocity of the airflow in the wind tunnel to 7.3 m / s and setting four types of angles of attack (5 °, 10 °, 15 °, and 20 °).

The calculated value of the lift L and drag D obtained in experiments, respectively were determined lift coefficient C _L and the drag coefficient C _D is substituted into the following equation (9) and (10). In the following formulas (9) and (10), ρ represents the specific gravity of air, q represents the flow velocity of air, and S represents the blade area of the blade used in the experiment.

FIG. 18 is a graph showing experimental results. In FIG. 18, ■ indicates the experimental value of the lift coefficient C _L , ● indicates the experimental value of the drag coefficient C _D , and Δ indicates the theoretical value of the lift coefficient C _L obtained by the potential theory. As shown in FIG. 18, since the experimental values and the theoretical value of the lift coefficient C _L matches well, it was possible to confirm the utility of lift and drag measurement device of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Rotation base, 12 ... Large disk, 13 ... Opening part, 14 ... Small disk, 16 ... Protrusion, 17 ... Mark, 18 ... Scale, 19 ... Fitting part, 20 ... Rotating shaft, 30 ... Rotating shaft support means, DESCRIPTION OF SYMBOLS 40 ... 1st rotational torque provision means, 42 ... Shaft fixing means, 44 ... Shaft, 48 ... Weight, 50 ... 2nd rotational torque provision means, 52 ... Shaft fixing means, 54 ... Shaft, 56 ... Scale, 58 ... Weight: 60 ... Balance state presentation means, 62: Bearing, 64 ... String, 66 ... Weight, 68 ... Positioning disc, 80 ... Wings, 82a, 82b ... Hole, 92 ... First rectification unit, 93 ... Shrinkage Flow part, 94 ... wind tunnel, 95 ... second rectification part, 97 ... intake fan, 98 ... pedestal, 100 ... lift force measurement apparatus, 200 ... vertical wind tunnel apparatus

Claims (4)

A lift / drag force measuring device for measuring the lift / drag force acting on a model in a wind tunnel,
A rotating pedestal formed by detachably fitting a small disk for fixing the model to an opening formed in the large disk;
A rotating shaft fixed to the center of the back surface of the rotating pedestal;
A rotating shaft support means fixed to the wall surface of the wind tunnel and supporting the rotating shaft;
First rotating torque applying means for applying to the rotating shaft a rotating torque that balances with the rotating torque applied to the rotating shaft by gravity acting on the model;
Second rotational torque applying means for applying to the rotating shaft a rotational torque that balances with the rotational torque applied to the rotating shaft by a lifting force acting on the model;
A balance state presentation means for presenting a balance state of the rotational torque;
including,
Lift / drag force measuring device. The first rotational torque applying means includes
Shaft fixing means fixed rotatably with respect to the rotating shaft;
A pair of first shafts fixed orthogonally to the rotation shaft at opposite positions of the shaft fixing means;
A first weight fixed so as to change an axial fixing position relative to the first axis;
Including
The second rotational torque applying means is
Shaft fixing means fixed to the rotating shaft;
A pair of second shafts fixed at right angles to the rotation shaft at opposite positions of the shaft fixing means;
A second weight fixed so as to be freely changeable in an axial fixing position with respect to the second axis;
including,
The lift / drag force measuring device according to claim 1. The balance state presentation means includes
A bearing that is rotatably fitted to the rotating shaft;
A string having one end connected to the bearing and a weight connected to the other end;
A disc fixed to the rotating shaft, and an alignment disc on which an index for performing alignment with respect to the vertical direction presented by the string is displayed;
including,
The lift / drag force measuring device according to claim 1. The opening formed in the large disk is formed in a tapered shape so that its diameter gradually increases from the front surface to the back surface of the large disk, and a scale indicating an angle over the entire circumference of the edge of the opening. Engraved,
The lift / drag force measuring device according to any one of claims 1 to 3.