Experimental and Numerical Investigation of Automotive Aerodynamics Using DrivAer Model

2015 ◽  
Author(s):  
Lu Miao ◽  
Steffen Mack ◽  
Thomas Indinger
Keyword(s):  
Wind Tunnel ◽  
Numerical Investigation ◽  
Lift Force ◽  
Research Work ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
Navier Stokes ◽  
Basic Body ◽  
Limited Applicability ◽  
Drag And Lift

The use of experimental and numerical investigation to predict the aerodynamic characteristics of road vehicles is a standard practice in automotive design and development. Fundamental research has been often conducted on generic models with limited applicability to realistic cars. The DrivAer model developed in TU München possesses more representative car features. To encourage the use of the DrivAer model in independent research work, the experimental results and some numerical results were published. In this paper, a new developed wind tunnel setup of the DrivAer model was introduced. A new suspension system was designed in such a way that drag and lift force could be measured whilst the wheels are rolling on the moving ground without wheel struts (In this paper we call it wheels-on setup). The more close-truth experimental results of different rear end configurations were obtained. The lift force of the total model was firstly obtained. Additionally, the influences of the wheel struts and top sting were studied. Numerical investigation for performing finite-volume-based Reynolds-averaged Navier-Stokes (RANS) for the prediction of aerodynamic forces of passenger vehicles developed was presented, using the open-source CFD toolbox OpenFOAM®. Validation of the predictions was done on the basis of detailed comparisons to experimental wind tunnel data, both of the basic body (wheelhouse covered and without wheels) and the new wheels-on model. Results of drag coefficient were found to compare favourably to the experiments.

Analysis and Comparison of Experimental Results Both of Wind Tunnel Test and Running Test for HEMU-400X Pantograph

2012 ◽  
Author(s):  
Yeongbin Lee ◽  
Jin-sung Paik ◽  
Minho Kwak ◽  
Jinsun Yoo ◽  
Kyu Hong Kim ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Lift Force ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
Maximum Speed ◽  
Scaled Model ◽  
Vertical Lift ◽  
Contacting Force

In this paper, experimental results both of wind tunnel test and running test for HEMU-400X pantograph were compared and were analyzed. In wind tunnel test, 1/4scale pantograph for HEMU-400X which is being developed for the maximum speed of 400km/h in Korea were tested to investigate the vertical lift force of pantograph at the operational speed of 250, 270, 300, 330, 360 and 400km/h using lift estimation from 1/4 scaled model results. In the running test of train, the contacting force of pantograph was measured to current operational speed of 300km/h. Finally, the results of vertical lift force of pantograph in wind tunnel test and contacting force for the running test were compared to analyze the aerodynamic characteristics of the pantograph for HEMU-400X.

Analysis of lift and drag coefficients of a GT2 racing car at various speeds with movable wheels and ground

2015 ◽  
Vol 12 (3) ◽  
pp. 261-270
Author(s):  
Albert Boretti
Keyword(s):  
Wind Tunnel ◽  
Drag Force ◽  
Computational Fluid Dynamic ◽  
Lift Force ◽  
Fluid Dynamic ◽  
Time Simulation ◽  
Rear Wing ◽  
Speed Range ◽  
Drag And Lift ◽  
Lift And Drag

The paper proposes a study of a GT2 racing car with a computational fluid dynamic (CFD) tool. Results of STAR-CCM+ simulations of the flow around the car in a wind tunnel with movable ground and wheels are presented for different air speeds to assess the different contributions of pressure and shear to lift and drag over the speed range. The rear wing contributes more than 85% of the lift force and 7-8% of the drag force for this particular class of racing cars. When reference is made to the low speed drag and lift coefficients, increasing the speed from 25 to 100 m/s produces an increase of CD of more than 3% and a reduction of CL of more than 2%. The resultsuggests modifying the constant CD and CL values used in lap time simulation toolsintroducing the tabulated values to interpolate vs. the speed of the car.

Experimental Studies on Aerodynamic Characteristics of Pantograph System According to the Pantograph Cover Configurations for High Speed Train

2011 ◽  
Author(s):  
Yeongbin Lee ◽  
Minho Kwak ◽  
Kyu Hong Kim ◽  
Dong-Ho Lee
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Force ◽  
Experimental Studies ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Experimental Models ◽  
High Speed Train ◽  
Drag And Lift

In this study, the aerodynamic characteristics of pantograph system according to the pantograph cover configurations for high speed train were investigated by wind tunnel test. Wind tunnel tests were conducted in the velocity range of 20∼70m/s with scaled experimental pantograph models. The experimental models were 1/4 scaled simplified pantograph system which consists of a double upper arm and a single lower arm with a square cylinder shaped panhead. The experimental model of the pantograph cover is also 1/4 scaled and were made as 4 different configurations. It is laid on the ground plate which modeled on the real roof shape of the Korean high speed train. Using a load cell, the aerodynamic force such as a lift and a drag which were acting on pantograph system were measured and the aerodynamic effects according to the various configurations of pantograph covers were investigated. In addition, the total pressure distributions of the wake regions behind the panhead of the pantograph system were measured to investigate the variations of flow pattern. From the experimental test results, we checked that the flow patterns and the aerodynamic characteristics around the pantograph systems are varied as the pantograph cover configurations. In addition, it is also found that pantograph cover induced to decrease the aerodynamic drag and lift forces. Finally, we proposed the aerodynamic improvement of pantograph cover and pantograph system for high speed train.

scholarly journals Aerodynamic study of a suspension bridge deck by CFD simulations, wind tunnel tests and full-scale observations

2021 ◽  
Vol 1201 (1) ◽  
pp. 012007
Author(s):  
I. Kusano ◽  
E. Cheynet ◽  
J. B. Jakobsen ◽  
J. Snæbjörnsson
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Wide Range

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.

Numerical Investigation of Drag and Lift Forces on a Sedan Car using Computational Fluid Dynamics

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
M.F. Mohamed ◽  
P.L. Madhavan ◽  
E. Manoj ◽  
K. Sivakumar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Numerical Investigation ◽  
High Speed ◽  
The Body ◽  
Sharp Edge ◽  
Wind Tunnel Simulation ◽  
Lift Forces ◽  
Drag And Lift

The purpose of this work is to cut back the drag, lift and aerodynamic in-stability of a sedan car at high speed levels. In early times, the cars accustomed have a flat faces, sharp edge, conjointly had higher mileage and potency. However later because of the emergence of fuel crisis, scientists improved the model of cars with regard to dynamics of the fluid around the body. Thus, it changes the structure of cars with respect to aeromechanics. Simulation of a vehicle had been done using computational fluid dynamics to obtain the coefficient of drag and coefficient of lift. Finally, these coefficients from computational fluid dynamics are compared wind tunnel simulation.

Numerical Investigation of Losses Due to Unsteady Effects in Axial Turbines

2003 ◽  
Author(s):  
Michael Moczala ◽  
Ernst von Lavante ◽  
Manuchehr Parvizinia
Keyword(s):  
High Pressure ◽  
Numerical Investigation ◽  
Research Work ◽  
Navier Stokes ◽  
Loss Assessment ◽  
Physical Explanation ◽  
Axial Turbine ◽  
Loss Coefficients ◽  
Axial Turbines ◽  
Unsteady Effects

Understanding of losses caused by unsteady effects is essential in efforts to improve the efficiency of modern turbomachines. In the present research work, the unsteady midspan flow in a typical high pressure axial turbine was investigated using a compressible Navier Stokes solver. The aim of this study was to take a closer look at trends in the loss behavior depending on several flow and geometry parameters as well as to give a physical explanation of these trends. Two different definitions of loss coefficients were also employed for the loss assessment and its suitability for evaluation of “unsteady losses” was discussed considering accuracy and physical aspects.

An Experimental and Numerical Investigation of the Aerodynamic Characteristics of a Flameless Combustor

2019 ◽  
Author(s):  
M. P. Huijts ◽  
A. A. V. Perpignan ◽  
A. G. Rao
Keyword(s):  
Flow Field ◽  
Numerical Investigation ◽  
Flow Structure ◽  
Gas Turbines ◽  
Turbulence Models ◽  
Fuel Mixture ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Chamber Length ◽  
Image Velocimetry

Abstract The flameless combustion (FC) regime is a promising technology for gas turbines, as it potentially yields lower NOx emissions while maintaining high combustion efficiencies. However, the application of FC to gas turbines is still challenging as required conditions for its occurrence depend on several factors such as reactants mixing, residence times, heat losses, and chemical time-scales. Since the mixing of the reactants and incoming fresh air-fuel mixture plays an important role in FC, the aerodynamic characteristics of the combustor are instrumental in determining the combustor emission performance. Focusing on the aerodynamic characteristics, this paper is dedicated to the visualization and description of the flow inside a jet-based combustor designed to operate under FC. The cylindrical combustor has a FLOX® burner head with 12 concentrically placed nozzles, while an acrylic cylinder allowed full optical access to the flow field. The investigation was performed for non-reactive flow. Using Particle Image Velocimetry and a Reynolds-averaged Navier-Stokes CFD analysis, the flow was visualized and modelled. The simulations were run with the Standard and Realizable k-ε (SKE and RKE, respectively), as well as a Reynolds Stress turbulence model. The effect of modifying the SKE model C1ε constant was also investigated. In the experimental campaign, the influence of combustion chamber length, nozzle diameter, and jet velocity were investigated with respect to flow structure, recirculation ratios and entrainment behavior. The results show that the flow structure is mainly dependent on nozzle diameters, while the jet momentum is the correct parameter to assess the recirculation impact of a certain jet flow. The numerical investigation shows that the turbulence intensity at the boundaries is an important parameter to accurately simulate the jet spreading. None of the used turbulence models fully represented the flow field. Nonetheless, the SKE model with model C1ε = 1.44 was the best at representing the jets penetration and vortex core positions, and the recirculation ratio values predicted by it were in good agreement.

scholarly journals Numerical Calculation of Effect of Elastic Deformation on Aerodynamic Characteristics of a Rocket

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Laith K. Abbas ◽  
Dongyang Chen ◽  
Xiaoting Rui
Keyword(s):  
Lift Force ◽  
Normal Force ◽  
Center Of Pressure ◽  
Aerodynamic Characteristics ◽  
Force Distribution ◽  
Pitching Moment ◽  
Flight Trajectory ◽  
Aerodynamic Coefficients ◽  
Computational Fluid Dynamics Cfd ◽  
Drag And Lift

The application and workflow of Computational Fluid Dynamics (CFD)/Computational Structure Dynamics (CSD) on solving the static aeroelastic problem of a slender rocket are introduced. To predict static aeroelastic behavior accurately, two-way coupling and inertia relief methods are used to calculate the static deformations and aerodynamic characteristics of the deformed rocket. The aerodynamic coefficients of rigid rocket are computed firstly and compared with the experimental data, which verified the accuracy of CFD output. The results of the analysis for elastic rocket in the nonspinning and spinning states are compared with the rigid ones. The results highlight that the rocket deformation aspects are decided by the normal force distribution along the rocket length. Rocket deformation becomes larger with increasing the flight angle of attack. Drag and lift force coefficients decrease and pitching moment coefficients increase due to rocket deformations, center of pressure location forwards, and stability of the rockets decreases. Accordingly, the flight trajectory may be affected by the change of these aerodynamic coefficients and stability.

scholarly journals Unsteady RANS Simulations of Flow around a Twin-Box Bridge Girder Cross Section

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2670 ◽  
Author(s):  
Wonmin Jeong ◽  
Shengnan Liu ◽  
Jasna Bogunovic Jakobsen ◽  
Muk Chen Ong
Keyword(s):  
Cross Section ◽  
Flow Characteristics ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Stream Velocity ◽  
Long Span Bridges ◽  
Long Span ◽  
Sst Turbulence Model ◽  
Bridge Girder ◽  
Drag And Lift

The aerodynamic performance of bridge deck girders requires a thorough assessment and optimization in the design of long-span bridges. The present paper describes a numerical investigation of the aerodynamic characteristics of a twin-box bridge girder cross section in the range of angles of attack between −10.0° and +10.2°. The simulations are performed by solving 2D unsteady Reynolds-averaged Navier–Stokes (URANS) equations together with the k–ω shear stress transport (SST) turbulence model. The investigated Reynolds number (Re) based on the free stream velocity ( U ∞ ) and the height of the deck (D) is 31,000. The predicted aerodynamic characteristics such as the mean drag, lift and moment coefficients, are generally in good agreement with the results from the wind tunnel tests. Changes of flow patterns and aerodynamic forces with different angles of attack are investigated. Flow characteristics during one vortex shedding period are highlighted. Relative contributions of each of the two bridge decks to the overall drag and lift coefficients, with respect to the angle of attack, are also discussed.

Unsteady Aerodynamic Characteristics of a High Speed Train with Crosswind

2011 ◽  
Vol 66-68 ◽  
pp. 1878-1882
Author(s):  
Ming Lu Zhang ◽  
Yi Ren Yang ◽  
Chen Guang Fan ◽  
Li Lu
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Vehicle Speed ◽  
High Speed Train ◽  
Mesh Method

The aerodynamic performances of a high speed train will significant change under the action of the crosswind. Large eddy simulation (LES) was made to solve the flow around a simplified CRH2 high speed train with 250km/h and 350km/h under the influence of a crosswind with 28.4m/s base on the finite volume method and dynamic layering mesh method and three dimensional incompressible Navier-Stokes equations. Wind tunnel experimental method of static train with relative flowing air and dynamic mesh method of moving train were compared. The results of numerical simulation show that the flow field around train is completely different between Wind tunnel experiment and factual running. Many vortices will be produced on the leeside of the train with alternately vehicle bottom and back under the influence of a crosswind. The flow field around train is similar with different vehicle speed.

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