CFD Analysis of Drag Reduction for a Generic SUV

2009 ◽  
Author(s):  
Pramod Nari Krishnani ◽  
Dongmei Zhou
Keyword(s):  
Wind Tunnel ◽  
Pressure Coefficient ◽  
Symmetry Plane ◽  
The Body ◽  
Cad Model ◽  
Governing Equations ◽  
Road Vehicles ◽  
Near Wake ◽  
Blunt Bodies ◽  
Commercial Software Package

The flow in the near wake of the blunt bodies of road vehicles like SUVs plays an important role in determining the pressure forces acting on the surface of the body. To better understand the wake profiles and stagnation pressure gradient of the vehicle, this paper performed numerical analysis on CAD model of a Generic SUV which was previously tested in the wind tunnel. Commercial software package of ANSYS® GAMBIT, T-grid and FLUENT® was used for multi cell meshing and solving of the governing equations. The pressure coefficient ‘Cp’ plots at the symmetry plane of the model were compared with experimental results from the wind tunnel tests to validate the simulation. Results and conclusions were presented from the simulations of the CAD model using upper and lower flat boat tail plates with gradual increment in the angle of inclination.

Hypersonic Swirling Flow past Blunt Bodies

1973 ◽  
Vol 24 (4) ◽  
pp. 241-251 ◽  
Author(s):  
Roger Smith
Keyword(s):  
High Speed ◽  
Swirling Flow ◽  
Pressure Coefficient ◽  
Density Ratio ◽  
Perturbation Expansion ◽  
The Body ◽  
Constant Density ◽  
Flow Past ◽  
Speed Flow ◽  
Blunt Bodies

SummaryThe effect of swirl on the high speed flow past blunt bodies is analysed by assuming constant density in the region between the shock wave and the body. For small swirl the stand-off distance is only slightly affected, but it is shown that there is a critical value of the swirl parameter which, if exceeded, will cause a jump in the position of the shock. This is demonstrated by solving the full constant-density equations for the flow past a sphere and by a perturbation expansion in powers of the density ratio across the shock for a more general body shape. The perturbation solution shows that the pressure coefficient on the body is constant at the critical swirl number.

scholarly journals Wind Tunnel Tests on Aerodynamic Forces of Road Vehicles Under Unsteady Wind Conditions

2018 ◽  
Vol 15 (4) ◽  
pp. 6064-6077
Author(s):  
M. Sumida ◽  
S. Morita
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Wind Condition ◽  
Road Vehicles ◽  
Fluid Forces ◽  
Lift Forces ◽  
Drag And Lift ◽  
Prism Model

This paper describes the results obtained from a wind tunnel test on the aerodynamic characteristics of road vehicles subjected to unsteady wind. In order to study the aerodynamic response of vehicles under atmospheric fluctuations, the velocity of the wind has been simulated in a pulsating state, where vehicles at a constant speed are driving in air with large wind oscillation. On the other hand, we consider three types of vehicles: two types of the Ahmed model, with slant angles of 0° and 30°, and the basic rectangular-prism model. The effect of wind oscillation on the drag and lift forces acting on the vehicle models under a pulsating wind condition has been extracted by comparing it to the forces under steady wind conditions. The oscillation of the wind exerts a significant effect on the fluid forces, and the drag and lift forces change with time in a peculiar way, depending on the body shape of the vehicle.

Nonboundary Conforming Methods for Large-Eddy Simulations of Biological Flows

2005 ◽  
Vol 127 (5) ◽  
pp. 851-857 ◽  
Author(s):  
Elias Balaras ◽  
Jianming Yang
Keyword(s):  
Body Surface ◽  
Computational Algorithm ◽  
The Body ◽  
Large Eddy Simulations ◽  
Moving Boundaries ◽  
Lagrangian Formulation ◽  
Governing Equations ◽  
Solid Interface ◽  
Large Eddy ◽  
Biological Flows

In the present paper a computational algorithm suitable for large-eddy simulations of fluid/structure problems that are commonly encountered in biological flows is presented. It is based on a mixed Eurelian-Lagrangian formulation, where the governing equations are solved on a fixed grid, which is not aligned with the body surface, and the nonslip conditions are enforced via local reconstructions of the solution near the solid interface. With this strategy we can compute the flow around complex stationary/moving boundaries and at the same time maintain the efficiency and optimal conservation properties of the underlying Cartesian solver. A variety of examples, that establish the accuracy and range of applicability of the method are included.

Computational Aerodynamics of a Winston-Cup-Series Race Car

2002 ◽  
Author(s):  
Oktay Baysal ◽  
Terry L. Meek
Keyword(s):  
Present Model ◽  
Pressure Coefficient ◽  
The Body ◽  
Race Car ◽  
Drag Forces ◽  
Surface Pressure Distribution ◽  
Computational Aerodynamics ◽  
Baseline Case ◽  
Quantitative Results ◽  
Lift And Drag

Since the goal of racing is to win and since drag is a force that the vehicle must overcome, a thorough understanding of the drag generating airflow around and through a race car is greatly desired. The external airflow contributes to most of the drag that a car experiences and most of the downforce the vehicle produces. Therefore, an estimate of the vehicle’s performance may be evaluated using a computational fluid dynamics model. First, a computer model of the race car was created from the measurements of the car obtained by using a laser triangulation system. After a computer-aided drafting model of the actual car was developed, the model was simplified by removing the tires, roof strakes, and modification of the spoiler. A mesh refinement study was performed by exploring five cases with different mesh densities. By monitoring the convergence of the computed drag coefficient, the case with 2 million elements was selected as being the baseline case. Results included flow visualization of the pressure and velocity fields and the wake in the form of streamlines and vector plots. Quantitative results included lift and drag, and the body surface pressure distribution to determine the centerline pressure coefficient. When compared with the experimental results, the computed drag forces were comparable but expectedly lower than the experimental data mainly attributable to the differences between the present model and the actual car.

scholarly journals Aerodynamic Performance of Road Vehicles

2020 ◽  
Vol 9 (6) ◽  
pp. 642-645
Keyword(s):  
Wind Tunnel ◽  
Drag Force ◽  
Aerodynamic Drag ◽  
Aerodynamic Performance ◽  
Polished Surface ◽  
Anova Analysis ◽  
Road Vehicles ◽  
Car Model ◽  
Group Data ◽  
Scale Models

Aerodynamic drag has been experimentally estimated for scale models of a passenger car and a commercial truck in a wind tunnel. Polished surface has resulted up to 15 % reduction in drag force and add-on has resulted in 57% increase in drag force of a car model whereas 2.6 % reduction in drag force has resulted by using deflector in a commercial truck model. Anova analysis shows variation in mean of group data.

Three-Dimensional Effects on Slamming Loads

2021 ◽  
Author(s):  
Shan Wang ◽  
C. Guedes Soares
Keyword(s):  
3D Model ◽  
Numerical Solutions ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
The Body ◽  
Navier Stokes ◽  
Courant Number ◽  
Dimensional Effects ◽  
Coefficient Distribution ◽  
Experimental Values

Abstract Three-dimensional effects on slamming loads predictions of a ship section are investigated numerically using the unsteady incompressible Reynolds-Average Navier-Stokes (RANS) equations and volume of fluid (VOF) method, which are implemented in interDyMFoam solver in open-source library OpenFoam. A convergence and uncertainty study is performed considering different resolutions and constant Courant number (CFL) following the ITTC guidelines. The numerical solutions are validated through comparisons of slamming loads and motions between the CFD simulations and the available experimental values. The total slamming force and slamming pressures on a 2D ship section and the 3D model are compared and discussed. Three-dimensional effects on the sectional force and the pressures are quantified both in transverse and longitudinal directions of the body considering various entry velocities. The non-dimensional pressure coefficient distribution on the 3D model is presented.

scholarly journals Full-Span Flying Wing Wind Tunnel Test: A Body Freedom Flutter Study

Fluids ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 34
Author(s):  
Pengtao Shi ◽  
Jihai Liu ◽  
Yingsong Gu ◽  
Zhichun Yang ◽  
Pier Marzocca
Keyword(s):  
Wind Tunnel ◽  
Theoretical Analysis ◽  
Mass Balance ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Suspension System ◽  
The Body ◽  
Structural Dynamic ◽  
Flutter Speed ◽  
Theoretical Results

Aiming at the experimental test of the body freedom flutter for modern high aspect ratio flexible flying wing, this paper conducts a body freedom flutter wind tunnel test on a full-span flying wing flutter model. The research content is summarized as follows: (1) The full-span finite element model and aeroelastic model of an unmanned aerial vehicle for body freedom flutter wind tunnel test are established, and the structural dynamics and flutter characteristics of this vehicle are obtained through theoretical analysis. (2) Based on the preliminary theoretical analysis results, the design and manufacturing of this vehicle are completed, and the structural dynamic characteristics of the vehicle are identified through ground vibration test. Finally, the theoretical analysis model is updated and the corresponding flutter characteristics are obtained. (3) A novel quasi-free flying suspension system capable of releasing pitch, plunge and yaw degrees of freedom is designed and implemented in the wind tunnel flutter test. The influence of the nose mass balance on the flutter results is explored. The study shows that: (1) The test vehicle can exhibit body freedom flutter at low airspeeds, and the obtained flutter speed and damping characteristics are favorable for conducting the body freedom flutter wind tunnel test. (2) The designed suspension system can effectively release the degrees of freedom of pitch, plunge, and yaw. The flutter speed measured in the wind tunnel test is 9.72 m/s, and the flutter frequency is 2.18 Hz, which agree well with the theoretical results (with flutter speed of 9.49 m/s and flutter frequency of 2.03 Hz). (3) With the increasing of the mass balance at the nose, critical speed of body freedom flutter rises up and the flutter frequency gradually decreases, which also agree well with corresponding theoretical results.

In the Wind Tunnel Simulation Defroster Control Study

2013 ◽  
Vol 380-384 ◽  
pp. 191-194
Author(s):  
Qin Yu Yang ◽  
Jin Bo Yao ◽  
Yue Ming Yang ◽  
Xue Wei Liu
Keyword(s):  
Wind Tunnel ◽  
External Environment ◽  
Aerodynamic Performance ◽  
The Body ◽  
Flight Safety ◽  
Aircraft Icing ◽  
Real Situation ◽  
Wind Tunnel Simulation ◽  
Performance Deterioration ◽  
Control Study

Aircraft in flight, such as supercooled water droplets encountered icing conditions suitable for the external environment, the relevant parts of the body will freeze, making the aircraft's aerodynamic performance deterioration, severe endanger flight safety, in addition, the aircraft parked in the open winter months , there will be icing, you need to clean up before takeoff. We should grasp the mechanism of aircraft icing, environmental factors and easy to freeze parts of the body. This paper presents a simulation using the wind tunnel icing device icing wind tunnel simulations can reproduce the real situation of aircraft icing, for guiding practice and got good results.

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