Investigation of computational flow fields and aeroacoustic characteristics over a re-entry command module

2016 ◽  
Vol 232 (3) ◽  
pp. 532-544 ◽  
Author(s):  
J Bruce Ralphin Rose ◽  
P Saranya ◽  
JV Bibal Benifa
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Separated Flow ◽  
Computational Design ◽  
Aerodynamic Characteristics ◽  
Flow Fields ◽  
Order Of Accuracy ◽  
Tunnel Model ◽  
Computational Fluid Dynamics Analysis

Design and analysis of a wind tunnel model for re-entry vehicle configuration is a prolonged and expensive mission. As the aerothermodynamics loads acting on the vehicle are based on geometry, various wind tunnel models need to be built for aerodynamic characterization by experimental procedure. Alternatively, the intention of this article is to present the influence of aerodynamic and aero acoustic characteristics of a typical re-entry capsule by computational fluid dynamics analysis. A typical re-entry capsule is designed using computational design software and it is imported to a computational fluid dynamics solver and flow simulations are done at various input conditions. Stanford University unstructured computational fluid dynamics solver is used for this purpose to solve complex, multiphysics analysis, and optimization tasks. Computational fluid dynamics results are presented to understand the influence of aerodynamic characteristics of a typical re-entry capsule, by visualizing the flow field around the command module at all the flow regimes like subsonic, supersonic, and hypersonic flows. The flow fields are studied in detail and regions of high flow unsteadiness due to wake separated flow zone are identified. Aeroacoustic loading on the command module at these regions especially at shock wave zone are predicted in the present investigation with high order of accuracy.

scholarly journals Performance prediction of loop-type wind turbine

2020 ◽  
Vol 12 (2) ◽  
pp. 168781401984047
Author(s):  
Wonyoung Jeon ◽  
Jeanho Park ◽  
Seungro Lee ◽  
Youngguan Jung ◽  
Yeesock Kim ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Experimental Results ◽  
Scale Model ◽  
Dynamics Analysis ◽  
Blockage Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Computational Fluid Dynamics Analysis

An experimental and analytical method to evaluate the performance of a loop-type wind turbine generator is presented. The loop-type wind turbine is a horizontal axis wind turbine with a different shaped blade. A computational fluid dynamics analysis and experimental studies were conducted in this study to validate the performance of the computational fluid dynamics method, when compared with the experimental results obtained for a 1/15 scale model of a 3 kW wind turbine. Furthermore, the performance of a full sized wind turbine is predicted. The computational fluid dynamics analysis revealed a sufficiently large magnitude of external flow field, indicating that no factor influences the flow other than the turbine. However, the experimental results indicated that the wall surface of the wind tunnel significantly affects the flow, due to the limited cross-sectional size of the wind tunnel used in the tunnel test. The turbine power is overestimated when the blockage ratio is high; thus, the results must be corrected by defining the appropriate blockage factor (the factor that corrects the blockage ratio). The turbine performance was corrected using the Bahaj method. The simulation results showed good agreement with the experimental results. The performance of an actual 3 kW wind turbine was also predicted by computational fluid dynamics.

Wind Tunnel Testing and Computational Fluid Dynamics Analysis of a Wing-in-Ground Effect Vehicle

2007 ◽  
Author(s):  
Boonseng Soh ◽  
Andrew Low ◽  
Cees Bil ◽  
Brendon Bobbermien
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Ground Effect ◽  
Wind Tunnel Testing ◽  
Cfd Modelling ◽  
Aerodynamic Analysis ◽  
Computational Fluid Dynamics Analysis ◽  
Wing In Ground Effect ◽  
Tunnel Testing

The Wing-in-Ground Effect Concept Technology Demonstrator (WIGE CTD) project is a joint venture between Advanced Aerosystem Technologies Pty Ltd and RMIT University, aiming to design, validate and build a prototype recreational vehicle to fly two passengers over a distance of 500km at approximately 120km/h. The WIGE vehicle will fly very close to the surface, usually water, taking advantage of ground effect to transport passengers with a greater lift/drag ratio, and thus greater fuel-efficiency than conventional aircraft. Following preliminary design, an aerodynamic analysis of the vehicle was performed using wind tunnel testing and Computational Fluid Dynamics (CFD). This paper describes the methods used for wind tunnel testing and CFD modelling of the WIGE CTD design. Results obtained using the two approaches are compared with the aim of validating the CFD model and the techniques used in both wind tunnel and CFD modelling for use in future analyses. In addition to the aerodynamic analysis, a basic CFD prediction of the maximum hydrodynamic drag experienced during take off was attempted using a simple model of the WIGE vehicle hull. This result is required in order to ensure that the aquatic take off required by WIGE vehicles was possible for the design. Concurrently, the feasibility of using a general-purpose CFD solver like Fluent to analyse hull performance was also evaluated through this aspect of the investigation.

On the aerodynamic characteristics of stay cables attached with helical wires

2017 ◽  
Vol 21 (9) ◽  
pp. 1262-1272 ◽  
Author(s):  
Shouying Li ◽  
Yangchen Deng ◽  
Wei Zhong ◽  
Zhengqing Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Vortex Shedding ◽  
Aerodynamic Characteristics ◽  
Wind Tunnel Tests ◽  
Stay Cables ◽  
Computational Fluid Dynamics Simulations ◽  
The Mean ◽  
Dynamics Simulations

To investigate the aerodynamic characteristics of stay cables attached with helical wires, a series of wind tunnel tests and computational fluid dynamics simulations were both carried out on the smooth and helical-wire cable models. The diameters of helical wires include 2, 3, and 4 mm, and the distances between adjacent helical wires include 200, 300, and 600 mm. Pressure taps were uniformly arranged on seven cross sections of the cable models. First, wind tunnel tests including 50 test cases were conducted to measure the wind forces and wind pressures on the cables using the forced vibration system in HD-2 wind tunnel. The effects of the helical wires on the mean and fluctuating aerodynamic forces and the correlation coefficients along the cable axis were investigated in detail based on the experimental data. Second, large Eddy simulation module incorporated in software FLUENT® was used to simulate the aerodynamic forces on the smooth and helical-wire cables. The parameters of the cable and the helical wire are similar to those used in the wind tunnel tests. The results show that helical wires can attenuate vortex shedding and reduce the wind pressure correlation along the cable axis. Within the Reynolds number range from 0.4 × 105 to 1.6 × 105, the mean drag force of the helical-wire cable is lower than the value of the smooth cable, and the correlation coefficient decreases with the increase in wind velocity. The results obtained from wind tunnel tests and computational fluid dynamics simulations agree well with each other. Furthermore, the wind velocity contour around the helical-wire cables obtained from computational fluid dynamics simulations visually indicates that the approaching flow is forced to separate at the surface of the helical wire in advance, which makes the vortex shedding disorder along the cable axis.

Extreme Load Computational Fluid Dynamics Analysis and Verification for a Multibody Wave Energy Converter

2019 ◽  
Author(s):  
Jennifer van Rij ◽  
Yi-Hsiang Yu ◽  
Alan McCall ◽  
Ryan G. Coe
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wave Energy ◽  
Computational Design ◽  
Wave Energy Converter ◽  
Model Verification ◽  
Order Effects ◽  
Energy Converter ◽  
Computational Fluid Dynamics Analysis ◽  
Extreme Load

Abstract A wave energy converter (WEC) must be designed to survive the extreme sea states that it will be subject to throughout its lifetime. Although there are many analysis methods and codes available to accomplish this, there are currently several engineering challenges to WEC survival design. Foremost, the computational design approach will typically involve a trade-off between accuracy and computational efficiency. Additionally, most computational fluid dynamics (CFD) codes are not ideally suited to modeling extreme events for WECs with multibody dynamics, power-take-off systems, and mooring systems. Finally, although WEC design standards and CFD guidelines are emerging, with the current immaturity of the WEC industry, they are not yet well established. In this study, loads on a 1:35-scale, moored, multibody WEC are evaluated with CFD. The CFD results are compared with results obtained from a computationally efficient, midfidelity model based on linearized potential flow hydrodynamics. For these model verification comparisons, both operational and survival configurations are considered. The extreme load results obtained, using both codes, indicate that the survival configuration successfully sheds loads during extreme sea states. It is also found that WEC-Sim, when appropriately applied, can provide reasonable load results, at a fraction of the computational expense of CFD. However, for the more extreme sea states, and for higher-order effects not included in the WEC-Sim model, the linear-based results have significant errors in comparison to the CFD-based results, and should be used judiciously.

Aerothermodynamic study of a small hypersonic plane

2018 ◽  
Vol 90 (2) ◽  
pp. 471-480 ◽  
Author(s):  
Vera D’Oriano ◽  
Raffaele Savino ◽  
Michele Visone
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Heating ◽  
Content Type ◽  
Long Duration ◽  
Computational Fluid Dynamics Analysis ◽  
Aerodynamic Performances ◽  
Point To Point ◽  
Dynamics Simulations

Purpose This paper aims to present an aerothermodynamic analysis of a new concept of a small hypersonic airplane. Aerodynamics characteristics for different flow conditions encountered during the missions are analyzed. The effects of elevons deflection for pitch control and of the presence of engines on aerodynamic performances are also investigated for different flight conditions. The effects of boundary layer laminar–turbulent transition on aerodynamic heating are studied to preliminarily identify proper materials that can sustain the hypersonic phase. Design/methodology/approach Aerodynamic characteristics are predicted by means of the semi-empirical aerodynamic prediction code Missile DATCOM and computational fluid dynamics simulations. Computational fluid dynamics analysis is also performed to investigate aerodynamic heating phenomenon. Findings Major discrepancies between the results offered by the two methods have been registered in transonic regime, whereas in subsonic and super-hypersonic conditions, Missile DATCOM confirms to be a suitable tool for preliminary design steps. The results of the analysis show that for the identification of the materials that can sustain the hypersonic phase, the turbulent solution must be taken into account. Carbon fiber reinforced ceramics composite materials seem particularly well suited for the nose, wing and vertical tail leasing edges and control surfaces, while titanium alloys could be used for the rest of the vehicle surface. Originality/value This new concept of vehicle is designed both for point-to-point medium range hypersonic transportation and long duration suborbital space tourism missions, by integrating available technologies developed for aeronautical and space systems.

A 2D Computational Fluid Dynamics Analysis of Wells Turbine Blade Profiles in Isolated and Cascade Flow

2002 ◽  
Author(s):  
John Daly ◽  
Patrick Frawley ◽  
Ajit Thakker
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Aerodynamic Characteristics ◽  
Angle Of Incidence ◽  
Aerodynamic Forces ◽  
Wells Turbine ◽  
Cascade Flow ◽  
Computational Fluid Dynamics Analysis ◽  
Airfoil Blades ◽  
Naca 0015

This paper deals with the application of Computational Fluid Dynamics (CFD) to the analysis of the aerodynamic characteristics of symmetrical airfoil blades in 2-Dimensional flow. The CFD model was used to compare blades of varying profiles to analyse the aerodynamic forces and the compressibility effects and to compare the differences in modelling the blades in isolated and cascade flow. The model was validated using correction factors with published results for the NACA 0015 blade profile, which show that the model gives good results for the aerodynamic forces. The differences in the predicted aerodynamic characteristics, such as low angle of incidence drag, as well as normal and tangential forces are compared for the isolated and cascade cases. The validated model was then used to compare proposed blade profiles for a Wells Turbine. The paper presents the results of the numerical investigation along with the analysis and comparison of the different profiles.

Prediction of Stack Plume Downwash Using Computational Fluid Dynamics

2003 ◽  
Author(s):  
Stuart A. Cain ◽  
Lewis A. Maroti ◽  
Fangbiao Lin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Cross Flow ◽  
Leeward Side ◽  
Wind Tunnel Model ◽  
Ambient Wind ◽  
Model Study ◽  
Tunnel Model ◽  
Computational Fluid Dynamics Cfd

Accurate prediction of the fluid dynamic and thermodynamic characteristics of saturated buoyant plumes at power plant chimneys is important in developing reliable methods for controlling stack plume downwash. In particular, the accurate prediction and abatement of stack plume downwash is critical in northern climates where, under downwash conditions, the interaction of the saturated, warm plume with the cold outer chimney surface can lead to hazardous ice formation and buildup near the top of the chimney. When a stack is in downwash mode the plume leaving the stack turns downward and flows down along the leeward side of the shell. This is a direct consequence of the wind dynamic pressure acting on the plume and the low pressure in the wake of the shell. In downwash model it is not uncommon to see the plume travel down the shell one third to one half the chimney height and extend radially away from the shell a distance of twenty to thirty feet. This complex interaction of a turbulent thermally buoyant jet entering a cross wind has been studied extensively in the past both experimentally and theoretically with emphasis on the introduction of the jet through an orifice in an infinitely long flat plate. In the case of stack plume downwash the drag of the cylindrical stack in cross flow interacts with the plume under certain “worst-case” ambient wind conditions for the geographic location of the plant and draws the swirling plume into the wake region behind the stack. Once in this region, the distance the plume will travel down the leeward side of the chimney is a function of the ambient wind velocity and the plume velocity. Prediction of this complex, turbulent, three dimensional swirling flow including mixing of different temperature gases and the development of remedial devices to control, in particular, the problem of plume downwash has traditionally required an extensive and expensive wind tunnel model study. Results of these wind tunnel tests include empirical correlations and charts which have been used in the industry for decades. Advances in the capabilities of Computational Fluid Dynamics (CFD) have allowed engineers the ability to reliably study this flow phenomena in greater detail than attainable in a typical wind tunnel model study. In this paper Computational Fluid Dynamics (CFD) is used to predict downwash as a function of flue gas discharge velocity, wind velocity and temperature and the geometry of the stack near the discharge elevation. Further, two devices for minimizing plume downwash in a prototype stack installation are discussed and evaluated by the authors using CFD. Model validation simulations against experimental data and theoretical predictions of buoyant jets in cross flow are also presented and discussed.

scholarly journals Aerodynamic research of a racing car based on wind tunnel test and computational fluid dynamics

2018 ◽  
Vol 153 ◽  
pp. 04011
Author(s):  
Jianfeng Wang ◽  
Hao Li ◽  
Yiqun Liu ◽  
Tao Liu ◽  
Haibo Gao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Cfd Simulation ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Aerodynamic Forces ◽  
Automotive Aerodynamics

Wind tunnel test and computational fluid dynamics (CFD) simulation are two main methods for the study of automotive aerodynamics. CFD simulation software solves the results in calculation by using the basic theory of aerodynamic. Calculation will inevitably lead to bias, and the wind tunnel test can effectively simulate the real driving condition, which is the most effective aerodynamics research method. This paper researches the aerodynamic characteristics of the wing of a racing car. Aerodynamic model of a racing car is established. Wind tunnel test is carried out and compared with the simulation results of computational fluid dynamics. The deviation of the two methods is small, and the accuracy of computational fluid dynamics simulation is verified. By means of CFD software simulation, the coefficients of six aerodynamic forces are fitted and the aerodynamic equations are obtained. Finally, the aerodynamic forces and torques of the racing car travel in bend are calculated.

Effect of the inter-car gap length on the aerodynamic characteristics of a high-speed train

2018 ◽  
Vol 233 (4) ◽  
pp. 448-465 ◽  
Author(s):  
Tian Li ◽  
Ming Li ◽  
Zheng Wang ◽  
Jiye Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Drag Force ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Wind Tunnel Experiments ◽  
The Impact

In wind tunnel experiments, the inter-car gaps are designed in such a way as to separate the force measurements for each car and prevent the interference between cars during tests. Moreover, the inter-car gap has a significant effect on the aerodynamic drag of a train. In order to guide the design of the inter-car gaps between cars in wind tunnel experiments, the impact of the inter-car gap length on the aerodynamic characteristics of a 1/8th scale high-speed train is investigated using computational fluid dynamics. The shear stress transport k-ω model is used to simulate the flow around a high-speed train. The aerodynamic characteristics of the train with 10 different inter-car gap lengths are numerically simulated and compared. The 10 different inter-car gap lengths are 5, 8, 10, 15, 20, 30, 40, 50, 60, and 80 mm. Results indicate that the aerodynamic drag coefficients obtained using computational fluid dynamics fit the experimental data well. Rapid pressure variations appear in the upper and lower parts of the inter-car gaps. With the increase of the inter-car gap length, the drag force coefficient of the head car gradually increases. The total drag force coefficients of the trains with the inter-car gap length less than 10 mm are practically equal to those of the trains without inter-car gaps. Therefore, it can be concluded from the present study that 10 mm is recommended as the inter-car gap length for the 1/8th scale high-speed train models in wind tunnel experiments.

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