Wind Tunnels

... School of Engineering Springfield, Massachussetts Drag Reduction and Wake Minimization on Marine Vehicles ,,P. ,3 1991 By: , Craig A. Hunter Pasquale Delore Walter M. Presz, Jr. Final Report Office of Naval Research Grant N0014-89-J-1883 00 July 1991 I I Page 2. Abstract ...

The data presented in this article were the basis for the study reported in the research articles entitled 'A validated design methodology for a closed loop subsonic wind tunnel' (Calautit et al., 2014) [1], which presented a systematic investigation into the design, simulation and analysis of flow parameters in a wind tunnel using Computational Fluid Dynamics (CFD). The authors evaluated the accuracy of replicating the flow characteristics for which the wind tunnel was designed using numerical simulation. Here, we detail the numerical and experimental setup for the analysis of the closed-loop subsonic wind tunnel with an empty test section.

This paper presents an account of model design, steady state simulation and a CFD analysis of three heat exchangers namely, double pipe heat exchanger, shell and tube heat exchanger and transverse fin type heat exchanger in order to evaluate their performance under a common parameter. The objective of this research work is to select the appropriate heat exchanger for exchange of excess heat from a liquid rheostat which controls the speed of an AC motor coupled to the fans of an open circuit wind tunnel. Five models in each of the three heat exchangers were designed and its pressure drop was calculated. This helped in determining the best model for further analysis. Each model from the three heat exchangers was analysed and parameters like temperature, pressure and velocity were compared. I. INTRODUCTION A wind tunnel is an aerodynamic test facility. It is mostly used to study flow patterns around bodies and measure aerodynamic forces on them. The bodies (called models) are usually scaled down but geometrically similar versions of bodies of interest like an airplane or an automobile. The results from wind tunnel tests can be 'scaled' to the actual velocity and actual body size using suitable scaling laws. A typical wind tunnel consists of a test section in which the model is kept, a contraction section and settling section before the test section, and a diffuser after the test section. A fan after the diffuser creates the wind. The function of the motor in the wind tunnel is to supply the necessary torque to the fan which will convert the torque into useful thrust. This thrust, which acts as a pressure difference at the fan station, has to supply the various losses encountered by the moving mass of air across the passage of the tunnel. A heat exchanger is a device that is used to transfer thermal energy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact. In heat exchangers, there are usually no external heat and work interactions. Typical applications involve heating or cooling of a fluid stream of concern and evaporation or condensation of single or multicomponent fluid streams. A major characteristic of heat exchanger design is the relative flow configuration, which is the set of geometric relationships between the streams.

In recent years, as a result of significant climate change, stringent windstorms are becoming more frequent than before. Given the threat that windstorms bring to people and property, wind/structural engineering research is imperative to improve the resilience of existing and new infrastructure, for community safety and assets protection. The Windstorm Impact, Science and Engineering (WISE) research program at Louisiana State University (LSU) focuses on creating new knowledge applicable to the mitigation of existing and new infrastructure, to survive and perform optimally under natural hazards (Figure 1). To achieve our research goals, we address two imperious challenges: (i) characterization of realistic wind forces on buildings and other types of structures; and (ii) developing advanced control theory to accelerate the optimal tuning of smart structures, with the aim of developing novel probabilistic analytical methods to address the complex behavior and inherent nonlinearity in semi-active control, for multiple hazards.

This paper deals with a computational fluid dynamics (CFD) and experimental drag analysis on an isolated rotating wheel subsystem (including its accessories: tire, suspension, A-arms, and fender) of a motor tricycle vehicle with two wheels in front. The main goal of the present work is to study the effect of the fender on the wheel subsystem drag and its optimization. The Star CCM+ commercial code was used for the numerical simulations. Different flow conditions were simulated and some results were validated by comparison to wind tunnel experimental results. To perform drag optimization, several aerodynamic fender shapes were designed and simulated as part of the subsystem. A drastic drag reduction up to 30.6% compared to the original wheel subsystem was achieved through numerical simulations.

The turbulent flow structures responsible for the fluctuating wall pressure in the turbulent boundary layer on a cylinder in axial flow (delta/a = 5.04, Re(sub theta) = 2870) have been investigated. Simultaneous measurements of the fluctuating wall pressure and turbulent streamwise velocities have been performed throughout a large volume of the boundary layer (y(sup +) = 14 to y/delta = 1.91, 0 less than or equal to x/delta less than or equal to 1.52, azimuthal angle phi = 0 deg, 20 deg, 40 deg) with a subminiature electret microphone (d(sup +) = 25.9) and hotwire velocity probe (1(sup +) = 18.5). Pressure-velocity cross-spectra and cross-correlation measurements indicate that two primary groups of pressure fluctuations exist in the cylindrical boundary layer: (1) small-scale, high-frequency disturbances concentrated close to the wall associated with the burst-sweep cycle; and (2) large-scale, low-frequency disturbances extending from the wall to the turbulent/potential-flow interface that are consistent with a large spanwise-oriented 'vortex' in close contact with and inclined to the wall.

ype of simple strai ght-flow wind tunnel test equipment for vertical axis wind turbines has been developed. The performance of the power section, diffusin g section, rectification section and the contraction section of the wind tunnel is anal yzed and calculated, and an inte grated test bed is established, with which, the performance of a new wind wheel is tested

... Editorial Board Dr. Richard H. Nadolink, Chairman Dr. Ding Lee Dr. James CS Meng Dr. Albert H. Nuttall Dr. Norman L. Owsley Dr. Bruce E ... where s is a general surface coordinate along the generator line of the axisymmetric structure, ani and bni are constants, I = Ix +12 + Is is ...

Responding to more demand in coming years, the task of the small wind energy industry requires progress on several fronts—from public policy initiatives, to technology development, to market growth. Enhanced technologies such as contra-rotating blades, transmission systems, lubrication, airfoils, generators, and power electronics will lower cost and increase energy production. This paper mainly considers two key technological points of a

Over the past few decades there has been considerable progress made in understanding the processes leading to formation and evolution of particulate matter (PM) emissions from heavy duty diesel engines (HDDE). This progress has been primarily made under controlled laboratory conditions with the use of constant volume sampling (CVS) systems and to a limited extend through on-road chase studies. West Virginia University (WVU) is attempting to close the present knowledge gap by conducting detailed experiments in a custom designed and constructed environmental wind tunnel. The understanding and knowledge has recently been further extended to new emission reduction technologies, such as the diesel particulate filter (DPF) which has dramatically changed the size distribution and chemical composition of PM. Additionally, the selective catalytic reduction (SCR) technology has shown to further enhance the formation of nucleation mode particles as well as alter their morphology. Even with advances in technology there remains a considerable gap in the current level of understanding of PM formation and evolution, since the combustion generated PM from diesel engines is not discernible from the atmospheric background PM measured beyond 300m from highways. After being emitted from the vehicle exhaust system, the process of dilution in the atmosphere leads to a multitude of PM transformation phenomena, such as volatilization, coagulation, and condensation. The work presented herein has been divided into two parts which are published separately from each another.The first part describes the design and commissioning process of the wind tunnel focusing on both, aerodynamic and structural constraints, which ultimately led to the definition of the main characteristics of the facility. The resulting design is a subsonic, non-recirculating, suction type tunnel, with a 16ft high and 16ft wide test section capable of housing a full-size heavy-duty tractor cab. A 2,200hp suction fan is employed to provide up to 80 mph wind speeds. The 115ft test cell length guarantees for a 2 second residence time for the exhaust plume evolution (at 35 mph) and complies with turbulence intensity (less than 1%) and quality flow requirement as identified for this type of application. In addition, the West Virginia University (WVU) wind tunnel has been equipped with a custom made sampling system able to move in all three dimensions in order to measure spatially resolved plume characteristics.The second part will describe the actual test procedures and the experimental results and will be published in a separate paper.Copyright © 2012 by ASME

The NatHaz Aerodynamic Loads Database (NALD) (http://aerodata.ce.nd.edu) introduced in 2000 has served an important first step in establishing an on-line experimental archive of high-frequency base balance (HFBB) data for use in the preliminary design of high-rise ...

A joint effort between the Georgia Tech Research Institute (GTRI) and the Army Research Lab (ARL) successfully used a combination of numerical and experimental results to demonstrate the performance of a guidance actuator for a supersonic projectile. The use of computational and experimental approaches greatly enhanced the understanding of how the actuators worked as well enabled the program to be completed for a lower cost than if either the modeling or the experiments had been neglected. Wind tunnel experiments were used with CFD results to provide aerodynamic coefficients for 6-DOF simulations. The 6-DOF simulations were used to predict the performance of the projectile in the range thus insuring that good range data was acquired and reducing the necessary number of setup rounds. It was found that there were cases where experimental methods were necessary, while the modeling provided the researchers with a greater detail of the flow interactions and provided forces that were diff...