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We present Python Statistical Analysis of Turbulence (P-SAT), a lightweight, Python framework that can automate the process of parsing, filtering, computation of various turbulent statistics, spectra computation for steady flows. P-SAT... more
We present Python Statistical Analysis of Turbulence (P-SAT), a lightweight, Python framework that can automate the process of parsing, filtering, computation of various turbulent statistics, spectra computation for steady flows. P-SAT framework is capable to work with single as well as on batch inputs. The framework quickly filters the raw velocity data using various methods like velocity correlation, signal-to-noise ratio (SNR), and acceleration thresholding method in order to de-spike the velocity signal of steady flows. It is flexible enough to provide default threshold values in methods like correlation, SNR, acceleration thresholding and also provide the end user with an option to provide a user defined value. The framework generates a .csv file at the end of the execution, which contains various turbulent parameters mentioned earlier. The P-SAT framework can handle velocity time series of steady flows as well as unsteady flows. The P-SAT framework is capable to obtain mean ve...
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Abstract Experimental investigations were carried out to investigate the development of boundary layer in non-uniform sand bed channels with and without seepage. Steady flows over non-uniform sand bed channel were simulated experimentally... more
Abstract Experimental investigations were carried out to investigate the development of boundary layer in non-uniform sand bed channels with and without seepage. Steady flows over non-uniform sand bed channel were simulated experimentally with downward seepage applied through the boundary. Velocity measurements were made at 12 different sections along the channel mid-section for no seepage and seepage flow conditions to investigate the fully developed flow condition. High boundary layer thickness and small boundary layer development length are observed for no seepage runs as compared to seepage runs. The value of boundary layer development length varies between 56 and 65 times of the flow depth for all flow conditions. The present study develops empirical equations to predict boundary layer thickness and flow development length in seepage affected alluvial channel under present experimental conditions.
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Longitudinal and cross-sectional profiles of alluvial channels are altered by the presence of seepage. However, the available literature suggests that seepage has not been considered in analyses of bank profiles of threshold alluvial... more
Longitudinal and cross-sectional profiles of alluvial channels are altered by the presence of seepage. However, the available literature suggests that seepage has not been considered in analyses of bank profiles of threshold alluvial channels. In the experimental study reported here, downward seepage was applied to parabolic channels based on tractive force theory in order to determine its effect on the longitudinal and cross-sectional profiles. It was observed that sediment transport in the threshold channels increased when downward seepage was applied. The parabolic shape did not hold, but channels formed a new cross-sectional shape with a flat bed and two curved banks and achieved stability. The reason for the increased sediment transport in a threshold channel after the application of downward seepage was sought by analysing the time-averaged velocities. An empirically derived exponential expression was developed for the bank profiles of threshold alluvial channels affected by s...
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The pollution of surface water has become a global environmental issue. Monitoring of surface water is essential to know the current status of water quality and maintain it at certain desirable level. In this study surface water quality... more
The pollution of surface water has become a global environmental issue. Monitoring of surface water is essential to know the current status of water quality and maintain it at certain desirable level. In this study surface water quality of Amingaon has been analysed. Amingaon is a locality in North Guwahati (Assam, India). In last few decades’ the locality has undergone rapid and uncontrolled development activities which have a detrimental impact on its ecology and environment. Samples were collected from 12 lakes and analysed for 24 parameters namely temperature (T), pH, electrical conductivity (EC), turbidity (Tur), total suspended solids (TSS) and total dissolved solids (TDS), total alkalinity (TA), total hardness (TH), chloride ion (Cl−), fluoride (F−), sulphate (SO42−), sodium (Na+), potassium (K+), calcium (Ca2+), dissolved oxygen (DO) biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonium nitrogen (NH3-N), total Kjeldahl nitrogen (TKN), nitrate (NO3−) total p...
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Experiments were performed in a sand bed channel to investigate the effects of a mining pit on the hydrodynamics around circular bridge piers. Mean velocity profiles, Reynolds stresses, kinetic energy fluxes and scales of turbulence were... more
Experiments were performed in a sand bed channel to investigate the effects of a mining pit on the hydrodynamics around circular bridge piers. Mean velocity profiles, Reynolds stresses, kinetic energy fluxes and scales of turbulence were analysed at critical locations along the channel bed as well as in the proximity of the pier. At the approach location where flow had passed over the pit and was approaching the pier, substantial increments in the near-bed velocities, bed shear stress and Reynolds stresses were observed. Dredging of the pit increased the strength of the horseshoe vortex in the scour hole region and also amplified the shedding frequency of trailing vortices at the rear of the pier. These effects may be instrumental in the alteration of local scour as well as erosion and deposition patterns around bridge piers.
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Understanding the flow in stirred vessels can be useful for a wide number of industrial applications. There is a wealth of numerical simulations of stirring vessels with standard impeller such as Rushton turbine and pitch blade turbine.... more
Understanding the flow in stirred vessels can be useful for a wide number of industrial applications. There is a wealth of numerical simulations of stirring vessels with standard impeller such as Rushton turbine and pitch blade turbine. Here, a CFD study has been performed to observe the spatial variations (angular, axial and radial) of hydrodynamics (velocity and turbulence field) in unbaffled stirred tank with Concave-bladed Disc turbine (CD-6) impeller. Three speeds (N=296, 638 & 844.6 rpm) have been considered for this study. The angular variations of hydrodynamics of stirred tank were found very less as compared to axial and radial variations.
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In-vessel composting of agricultural waste is a well-described approach for stabilization of compost within a short time period. Although composting studies have shown the different combinations of waste materials for producing good... more
In-vessel composting of agricultural waste is a well-described approach for stabilization of compost within a short time period. Although composting studies have shown the different combinations of waste materials for producing good quality compost, studies of the particular ratio of the waste materials in the mix are still limited. In the present study, composting was conducted with a combination of vegetable waste, cow dung, sawdust and dry leaves using a 550 L rotary drum composter. Application of a radial basis functional neural network was used to simulate the composting process. The model utilizes physico-chemical parameters with different waste materials as input variables and three output variables: volatile solids, soluble biochemical oxygen demand and carbon dioxide evolution. For the selected model, the coefficient of determination reached the high value of 0.997. The complicated interaction of agricultural waste components during composting makes it a nonlinear problem s...
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Also, a report exists of the killing of a white tiger in Assam in March 1851. The unnoticed report is a much earlier record of the killing of a white tiger in India. According to The Orunodoi, a white tiger was beaten to death in... more
Also, a report exists of the killing of a white tiger in Assam in March 1851. The unnoticed report is a much earlier record of the killing of a white tiger in India. According to The Orunodoi, a white tiger was beaten to death in Dibrugarh District, Assam and its head and skin were brought ...
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ABSTRACT Oxygen transfer and power requirement with rotor speed has always been a central topic for design and scale-up of surface aerators. Present study develops design curves correlating the oxygen transfer coefficient, power per unit... more
ABSTRACT Oxygen transfer and power requirement with rotor speed has always been a central topic for design and scale-up of surface aerators. Present study develops design curves correlating the oxygen transfer coefficient, power per unit volume and rotor speed. Based on the design curves, energy conservation by using right sized circular tank surface aerators has been discussed and demonstrated that it is economical to use a big sized circular tank surface aerator rather than using multiple numbers of smaller sized circular tank to aerate the same volume of water. KeywordsEnergy consumption-Surface aerators
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In the case of pipe trifurcation, previous observations report negative energy losses in the centre branch. This causes an anomaly, because there should not be any negative energy loss due to conservation of energy principle. Earlier... more
In the case of pipe trifurcation, previous observations report negative energy losses in the centre branch. This causes an anomaly, because there should not be any negative energy loss due to conservation of energy principle. Earlier investigators have suggested that this ...
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ABSTRACT Introduction: Textile sector in India plays an important role in the country's economy, providing employment to a significant population in rural and urban areas. Objectives: This paper focuses on health and safety... more
ABSTRACT Introduction: Textile sector in India plays an important role in the country's economy, providing employment to a significant population in rural and urban areas. Objectives: This paper focuses on health and safety aspects of textile workers in Solapur City (one of the key textile cluster) in the state of Maharashtra, India. Methodology: A sample of 180 workers from the identified textile industries of Solapur city were assessed for their general physique, muscle tone, lung condition, and eyesight using different techniques. The study aimed at developing a framework for understanding risks to textile workers resulting from lack of health and safety standards in companies. Results: Findings showed that most of the workers have been affected by respiratory problems, increase in muscle tone, eye problems and musculoskeletal problem. It has been also observed that job security or regular work impacts positively to the worker’s long term body health. However, there is an immediate need to adopt and implement measures in accordance with Indian Factories Act (OHSAS 18001/ILO-OSH 2001) which includes directions and procedures in respect of industrial installations, work environment and occupational health and safety guidelines.
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ABSTRACT The study has been carried out to analyze and predict the flood-inundation caused due to the failure of dam. The Hongadhalla dam was selected for the study of flood occurred due to sudden influx of flow caused because of dam... more
ABSTRACT The study has been carried out to analyze and predict the flood-inundation caused due to the failure of dam. The Hongadhalla dam was selected for the study of flood occurred due to sudden influx of flow caused because of dam break. The dam break analysis has been performed on DAMBRK model. Simulation model has been used to analyze the flood flow in natural flood plain of Hongadhalla dam with significant variation in bed slope, bed width, and resistance characteristics along the channel length. The DAMBRK model consist diffusive finite difference (FDM) form of one-dimensional St. Venant equations for flood waves attenuation and used for one-dimensional dynamic flood routing. Resultant outflow hydrograph has been computed and the movement of the dam-break flood waves through the downstream river valley has been simulated through the model. Extent of inundation, depth of flow, velocity, discharge hydrograph, flow, flood elevation, time to flood elevation, and the arrival time of flood waves at different cross sections have been calculated. Also, the flood affected areas and cross sections which could be affected due to the failure of DAMBRK model is applied to analyse the Hongadhalla dam and the results were compared to no flow structure at the same cross section and location. In this analysis, two types of model have been used. In first case, it uses the reservoir storage routing and the flow structure must reside at the most upstream cross-section and in the second case it uses the model for no flow structure i.e. it performs the dynamic routing of an input hydrograph and generate the hydrograph at the downstream of the river. It has been observed in the present study that in the case of dam failure approx. 90-97 % discharge increased and also the time of flood arrival, time to maximum stage reduced. This has the potential to generate sudden catastrophic flood and huge losses in the downstream.
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Shear rate in a surface aeration system exerts a profound effect on its performance, affecting the mixing pattern, the power requirement and oxygen transfer process. Based on theoretical analysis, it is shown that the shear rate gamma in... more
Shear rate in a surface aeration system exerts a profound effect on its performance, affecting the mixing pattern, the power requirement and oxygen transfer process. Based on theoretical analysis, it is shown that the shear rate gamma in the fluid is a function of the rotational speed N of the impeller in surface aeration systems. Analysis shows that the shear rate varies linearly with N in laminar flow and its behaviour is non-linear in a turbulent flow regime. Experimental correlations of gamma with N have been developed in the present study for different sized surface aerators. Scale-up or scale-down criteria for oxygen transfer rate have been developed, which relate oxygen transfer rate to shear rate in surface aeration systems.
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Thus, the sole purpose of designing any surface aerator should be to identify the appropriate geometric as well as the dynamic conditions at which it produces maximum SAE. To do so, three important aspects should be known: (1) optimum... more
Thus, the sole purpose of designing any surface aerator should be to identify the appropriate geometric as well as the dynamic conditions at which it produces maximum SAE. To do so, three important aspects should be known: (1) optimum ratios of geometric parameters; and (2) ...
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The resistance characteristics in terms of power consumption, interpreted in terms of Power number , of unbaffled surface aeration systems consisting of flat bladed impellers, were studied in two shapes of surface aerations tanks: square... more
The resistance characteristics in terms of power consumption, interpreted in terms of Power number , of unbaffled surface aeration systems consisting of flat bladed impellers, were studied in two shapes of surface aerations tanks: square and circular. Experiments were conducted in ...
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Résumé/Abstract Resistance to flow in mobile bed channels varies between wide limits because the form of the boundary roughness, as well as resistance to flow and sediment transport, is a function of the fluid, flow, bed material and... more
Résumé/Abstract Resistance to flow in mobile bed channels varies between wide limits because the form of the boundary roughness, as well as resistance to flow and sediment transport, is a function of the fluid, flow, bed material and channel characteristics. A system ...
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ABSTRACT A new criterion for incipient motion relating Froude number and friction slope with the relative density of sediment particles in fluid is presented in an explicit manner without involving particle size. The new criterion also... more
ABSTRACT A new criterion for incipient motion relating Froude number and friction slope with the relative density of sediment particles in fluid is presented in an explicit manner without involving particle size. The new criterion also explains the resistance ...
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Radial Basis Function Network Based Design of Incipient Motion Condition of Alluvial Channels with SeepageIncipient motion is the critical condition at which bed particles begin to move. Existing relationships for incipient motion... more
Radial Basis Function Network Based Design of Incipient Motion Condition of Alluvial Channels with SeepageIncipient motion is the critical condition at which bed particles begin to move. Existing relationships for incipient motion prediction do not consider the effect of seepage. Incipient motion design of an alluvial channel affected from seepage requires the information about five basic parameters, i.e., particle sized, water depthy, energy slopeSf, seepage velocityvsand average velocityu.As the process is extremely complex, getting deterministic or analytical form of process phenomena is too difficult. Data mining technique, which is particularly useful in modeling processes about which adequate knowledge of the physics is limited, is presented here as a tool complimentary to model the incipient motion condition of alluvial channel at seepage. This article describes the radial basis function (RBF) network to predict the seepage velocity vs and average velocityubased on experimental data of incipient condition. The prediction capability of model has been found satisfactory and methodology to use the model is also presented. It has been found that model predicts the phenomena very well. With the help of the RBF network, design curves have been presented for designing the alluvial channel when it is affected by seepage.
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The efficiency of the surface aeration systems is generally governed by the geometric and dynamic parameters. The geometry is important because successful translation of the laboratory finding can be scaled up to field installations.... more
The efficiency of the surface aeration systems is generally governed by the geometric and dynamic parameters. The geometry is important because successful translation of the laboratory finding can be scaled up to field installations. Experimental optimization of the geometrical parameters (classical approach of one parameter variations at a time) has certain limitations, because it assumes a linear relationship among the various geometric parameters. In the real experimental process, it is not possible to vary all the parameters simultaneously. In such a case, the model of the system is built through computer simulation, assuming that the model will result in adequate determination of the optimum conditions for the real system. In this paper, two approaches have been used to model the phenomena in unbaffled circular surface aerators: i) Multiple regression and ii) Neural network. It has been found that neural network approach is showing better predictability compared to the multiple regression approach. In process of optimization, the pertinent dynamic parameter is divided into a finite number of segments over the entire range of observations. For each segment of the dynamic parameter, the neural network model is optimized for the geometrical parameters spanning over the entire range of observations. Thus each segment of the dynamic parameter has its set of optimal geometrical conditions. Results obtained are having less variation among them and they are very nearer to the experimental optimal conditions. Input parameter significance test of neural network model reveals that blade width of the rotor is the most significant geometric parameter for the aeration process.
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ABSTRACT Baffled surface aerator and mixing tanks are different on the basis of the rotor placement. In mixing tanks, rotors are placed very deep in the tank, thus vortex creation can be prevented by placing the baffles. By definition,... more
ABSTRACT Baffled surface aerator and mixing tanks are different on the basis of the rotor placement. In mixing tanks, rotors are placed very deep in the tank, thus vortex creation can be prevented by placing the baffles. By definition, rotors are placed at or near the surface of water in surface aeration systems; complete prevention of vortex creation cannot be achieved by installing the baffles. Vortex geometry, thus created, imparts a major effect on the system efficiency. How deep a vortex can penetrate into a liquid layer is undoubtedly important in the design as well as the operation of the surface aeration systems. In the present work, empirical correlations have been tried to relate the vortex depth to a number of physical factors. It is found that around critical speed, there is an observable change in mass transfer characteristics, power used for mixing and radius of the forced vortex zone.
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Rao, Ramakrishna A and Kumar, Bimlesh and Sreenivasulu, Gopu (2007) Friction Factor For Pipe Flow: Basic Formulations. In: Workshop on the Design Analysis of Water Distribution Network, Hosur, Tamilnadu, 17th-21st September 2007, Hosur,... more
Rao, Ramakrishna A and Kumar, Bimlesh and Sreenivasulu, Gopu (2007) Friction Factor For Pipe Flow: Basic Formulations. In: Workshop on the Design Analysis of Water Distribution Network, Hosur, Tamilnadu, 17th-21st September 2007, Hosur, Tamilnadu.
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River Ganges, one of the most valuable water resource systems in Indian subcontinent, supports the socio-economical status of India and Bangladesh. Being a large river basin of 1.25 million km 2 in India and Nepal, the river is fed by... more
River Ganges, one of the most valuable water resource systems in Indian subcontinent, supports the socio-economical status of India and Bangladesh. Being a large river basin of 1.25 million km 2 in India and Nepal, the river is fed by both monsoon rainfalls and Himalayan snow melting runoff. Since 1980s, many water resources development in terms of extensive agriculture, hydropower projects, water use in industries and water demand increase in the urban areas has been progressively taking place within the basin. The hydrological changes of the basin due to both anthropogenic and natural causes need to be assessed at the basin scale. In this study, two major objectives addressed are the performance of a hydrological model in predicting long-term hydrological trend and to obtain the temporal trend analysis of the Ganges flow for the monsoon period, dry season and for the annual water yield at Farakka Barrage. First, a semi-distributed hydrological model, Soil Water Assessment Tool (SW...
An experimental and numerical investigation has been carried out to analyze the existence of local isotropy concept in geometrically similar surface aeration systems. Commercial software has been used in determining the small scale... more
An experimental and numerical investigation has been carried out to analyze the existence of local isotropy concept in geometrically similar surface aeration systems. Commercial software has been used in determining the small scale parameters such as microscale of turbulence and energy dissipation. Experimental observations have been carried out for oxygen transfer measurements in geometrically similar surface aeration systems. Two-film theory has been adopted in the measurement of oxygen transfer rate. It is found that microscale of turbulence and oxygen transfer are inversely related in geometrically similar surface aeration systems. Present work establishes the existence of local isotropy concept in higher turbulent flow conditions. Based on the local isotropy concept, the relationship of microscale of turbulence and rotational speed of rotor should exhibit the constancy, has been found in the present work. Empirical equation to simulate oxygen transfer rate in geometrical simila...
Channel flow-vegetation interaction has been extensively studied in the past few decades and many equations have been developed which essentially differ from each other in derivation and form. If process can be related to various physical... more
Channel flow-vegetation interaction has been extensively studied in the past few decades and many equations have been developed which essentially differ from each other in derivation and form. If process can be related to various physical parameters on a general basis, a proper understanding of flow-vegetation interaction can be ascertained. As the process is extremely complex, getting deterministic or analytical form of process phenomena is too difficult. Neural network modeling (ANN), which is particularly useful in modeling processes about which adequate knowledge of the physics is limited, is presented here as a tool complimentary to model channel flow-vegetation interactions. The prediction capability of model has been found satisfactory.
The present work deals primarily redesign of main channel and subsidiary channel can be augmented by controlling the stream power which reduces the channel capacity by various reasons. In a way, channel corresponding to critical values... more
The present work deals primarily redesign of main channel and subsidiary channel can be augmented by controlling the stream power which reduces the channel capacity by various reasons. In a way, channel corresponding to critical values can be defined as stable channel. The relations between hydraulic geometries of stable channel with bedload rate are quantified with a general behaviour.
The study on Bedload transport behaviour is widely explored from the last few decades and many semi-empirical or empirical equilibrium transport equations are developed. The phenomenon is a very complex due to its varied physical... more
The study on Bedload transport behaviour is widely explored from the last few decades and many semi-empirical or empirical equilibrium transport equations are developed. The phenomenon is a very complex due to its varied physical properties like velocity, depth, slope, particle size in the alluvial system. Alluvial channels having Φ>0.4 have been considered as intense bed load channels. Φ is called as Einstein transport function. In practical applications, these formulae have appreciable deviation from each other in derivation and also their ranges of applications are different. It is imperative to know the best predictive equations in for the field applications. Present work, based on large database of different bed load measurements, does a comparative analysis in terms of prediction ability of different bed load equations.
The flow through a channel connecting two reservoirs is one of the well known problems in water resources engineering. The water depth at the entrance and through the open channel mainly depends on the longitudinal bed slope of channel.... more
The flow through a channel connecting two reservoirs is one of the well known problems in water resources engineering. The water depth at the entrance and through the open channel mainly depends on the longitudinal bed slope of channel. Present work has developed procedure to calculate normal discharge values of the tunnel for different water depths and for different Manning’s roughness values n. The hydraulic efficiency of the tunnel can be increased by decreasing the n value. It means the lining should be made as smooth as possible. However smooth plastering is expensive therefore it can be preferred that the type of smoothness must consider overall economy of the project.
Large scale laboratory setting postulates the various modern techniques in river engineering and coastal processes are becoming increasingly significant day by day in the world to escalate the stress being applied to unbleached and... more
Large scale laboratory setting postulates the various modern techniques in river engineering and coastal processes are becoming increasingly significant day by day in the world to escalate the stress being applied to unbleached and nominal hazards. The physical model is inexpensive and easy to build to integrate the result with field observatory. To anticipate the incipient motion condition, an analytical formula for flow resistivity will be evaluated over uniform sand bed based on the experimental data and the predictions are approached to the field and laboratory measurements. The objective of this observation is to examine the variation of friction coefficient defined from the empirical relationships and development of sediment transport equation for the stream flow as well. The recommended sediment transport capacity relationship can be a function of hydraulic characteristics. The physical model will be carried out in a fabricated large rectangular hydraulic flume consists of 20...
In an alluvial stream, bedforms are the phenomenon which has formed due to changes in the depth and velocity of flow i.e. deformation of bed occurred periodically either symmetric or asymmetric manner with the variation of hydraulic... more
In an alluvial stream, bedforms are the phenomenon which has formed due to changes in the depth and velocity of flow i.e. deformation of bed occurred periodically either symmetric or asymmetric manner with the variation of hydraulic parameters. Water interacts with sediments because of changes in flow characteristics bed creates its own configurations. Due to small increment in velocity at near the bed creates series of sand waves that are like triangular in shape with gentle upstream slopes and lee downstream. They are defined with ripples, dunes and antidunes etc. Most common features of bed forms are ripples and dunes and they are formed in the subcritical flow (Fr < 1). Ripples have small features in the flow resistance and generally formed in fine sediments. Apart from dunes have large features that occur at larger velocity and sediment size which are disturbed the water surface and flow resistance. Dunes plays a sifnificant role in river flow system, which may affect the st...
ABSTRACT Present work analyzes the flow hydrodynamics and mass transfer mechanisms in double Rushton and CD-6 impeller on wide range (0.0075–0.25 m/s) of superficial gas velocity (v g) in a gas-liquid phase bioreactor by employing... more
ABSTRACT Present work analyzes the flow hydrodynamics and mass transfer mechanisms in double Rushton and CD-6 impeller on wide range (0.0075–0.25 m/s) of superficial gas velocity (v g) in a gas-liquid phase bioreactor by employing computational fluid dynamics (CFD) technique. The volume averaged velocity magnitude and dissipation rate are found higher with increasing superficial gas velocity. Higher relative power draw (P g/P 0) is predicted in CD-6 than the Rushton impeller but no significant difference in volume averaged mass transfer coefficient (k L a) observed between these two types of impeller. The ratio of power draw with mass transfer coefficient has been found higher in CD-6 impeller (25–50 %) than the Rushton impeller.
ABSTRACT Experimental investigation has been done in unbaffled gas-liquid stirred tanks using dual concave blade impeller to analyze the mass transfer, power consumption and gas holdup. Optimal impeller clearance has been suggested for... more
ABSTRACT Experimental investigation has been done in unbaffled gas-liquid stirred tanks using dual concave blade impeller to analyze the mass transfer, power consumption and gas holdup. Optimal impeller clearance has been suggested for lower and upper impeller based on maximum mass transfer rate. Numerical modeling has been done to analyze the flow pattern for different combinations of impeller clearance. The lower impeller positioned at 0.3 of tank diameter and clearance between lower and upper impeller at 0.4 of tank diameter gave the maximum mass transfer coefficient. Scale-up criteria for mass transfer rate, power and gas holdup have been developed for optimal geometrical similar systems of unbaffled stirred tanks with dual concave impeller.
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ABSTRACT Incipient motion of alluvial channel flow, which relates the beginning of sediment movement, has been extensively studied in the past few decades, and many equations have been developed which essentially differ from each other in... more
ABSTRACT Incipient motion of alluvial channel flow, which relates the beginning of sediment movement, has been extensively studied in the past few decades, and many equations have been developed which essentially differ from each other in derivation and form. As the process is extremely complex, getting deterministic or analytical forms of process phenomena is too difficult. Gaussian process regression (GPR), which is particularly useful in modeling processes about which adequate knowledge of the physics is limited, is presented here as a complementary tool to model the incipient motion problems. The prediction capability of the model has been found to be satisfactory.
ABSTRACT Baffled surface aerator and mixing tanks are different on the basis of the rotor placement. In mixing tanks, rotors are placed very deep in the tank, thus vortex creation can be prevented by placing the baffles. By definition,... more
ABSTRACT Baffled surface aerator and mixing tanks are different on the basis of the rotor placement. In mixing tanks, rotors are placed very deep in the tank, thus vortex creation can be prevented by placing the baffles. By definition, rotors are placed at or near the surface of water in surface aeration systems; complete prevention of vortex creation cannot be achieved by installing the baffles. Vortex geometry, thus created, imparts a major effect on the system efficiency. How deep a vortex can penetrate into a liquid layer is undoubtedly important in the design as well as the operation of the surface aeration systems. In the present work, empirical correlations have been tried to relate the vortex depth to a number of physical factors. It is found that around critical speed, there is an observable change in mass transfer characteristics, power used for mixing and radius of the forced vortex zone.
Research Interests:
ABSTRACT Sustainability has emerged as one of the important planning concepts from its beginnings in economics and ecological thinking, and has widely been applied to assessing urban development. Different methods, techniques and... more
ABSTRACT Sustainability has emerged as one of the important planning concepts from its beginnings in economics and ecological thinking, and has widely been applied to assessing urban development. Different methods, techniques and instruments for urban sustainability assessment that help determine how cities can become more sustainable have emerged over a period of time. Among these, indicator-based approaches contribute to building of sustainable self-regulated systems that integrate development and environment protection. Hence, these provide a solid foundation for decision-making at all levels and are being increasingly used. The present paper builds on the background of the available literature and suggests the need for benchmarking indicator-based approach in a given urban area and incorporating various local issues, thus enhancing the long-term sustainability of cities which can be developed by introducing sustainability indicators into the urban planning process.