scholarly journals The Effect of Cornering on the Aerodynamics of a Multi-Element Wing in Ground Effect

Fluids ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 3
Author(s):  
Dipesh Patel ◽  
Andrew Garmory ◽  
Martin Passmore
Keyword(s):  
Numerical Data ◽  
Ground Effect ◽  
Force Balance ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Surface Pressure Distribution ◽  
Straight Line ◽  
Race Cars ◽  
Line Condition ◽  
Wing In Ground Effect

This research investigates the effects of cornering on a multi-element wing in ground effect with the aim to improve the understanding of such in the effort to improve the performance of open-wheel race cars. A numerical validation study was performed to confirm the validity of the Detached Eddy Simulation CFD methodology used. This involved comparing numerical data with wind tunnel experimental data using a force balance and PIV for the velocity field to reveal the trajectory of the trailing vortex system. Once validated, the CFD was used to test the wing within a cornering condition as well as fixed yaw condition and its aerodynamic performance relative to the straight-line condition was analysed. Asymmetry was the general theme concerning the on-surface pressure distribution with this most prominent under the cornering condition. Ultimately, minimal change was observed regarding the downforce generated whilst drag was found to increase in the cornering condition and decrease slightly in the fixed yaw condition. Asymmetry was also observed in the wake of the wing where alterations to the relative strengths of the vortices was observed as well as their downstream paths which was generally governed by the direction of the freestream flow.

Detached-Eddy Simulation of Ground Effect on the Wake of a High-Speed Train

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Chao Xia ◽  
Xizhuang Shan ◽  
Zhigang Yang
Keyword(s):  
Vortex Shedding ◽  
High Speed ◽  
Vortex Pair ◽  
Ground Effect ◽  
Longitudinal Vortex ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Side Force ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation

The influence of ground effect on the wake of a high-speed train (HST) is investigated by an improved delayed detached-eddy simulation. Aerodynamic forces, the time-averaged and instantaneous flow structure of the wake are explored for both the stationary ground and the moving ground. It shows that the lift force of the trailing car is overestimated, and the fluctuation of the lift and side force is much greater under the stationary ground, especially for the side force. The coexistence of multiscale vortex structures can be observed in the wake along with vortex stretching and pairing. Furthermore, the out-of-phase vortex shedding and oscillation of the longitudinal vortex pair in the wake are identified for both ground configurations. However, the dominant Strouhal number of the vortex shedding for the stationary and moving ground is 0.196 and 0.111, respectively, due to the different vorticity accumulation beneath the train. A conceptual model is proposed to interpret the mechanism of the interaction between the longitudinal vortex pair and the ground. Under the stationary ground, the vortex pair embedded in a turbulent boundary layer causes more rapid diffusion of the vorticity, leading to more intensive oscillation of the longitudinal vortex pair.

Study of Unsteady Vortical Structures in Axisymmetric Hydrodynamic Chamber

2013 ◽  
Vol 8 (4) ◽  
pp. 76-83
Author(s):  
Alexey Vinokurov ◽  
Sergey Shtork ◽  
Sergey Alekseenko
Keyword(s):  
Fluid Dynamic ◽  
Numerical Data ◽  
Detached Eddy Simulation ◽  
Isothermal Model ◽  
Pressure Drops ◽  
Vortical Structures ◽  
Eddy Simulation ◽  
Precessing Vortex Core ◽  
Axisymmetric Vortex ◽  
Vortex Burner

The paper is devoted to experimental and numerical investigation of unsteady vortical processes in the isothermal model of axisymmetric vortex burner. Obtained characteristics of precessing vortex core (PVC) show the dependences of PVC`s frequency on flowrate, swirl number and nozzle`s diameter. Pressure drops inside the chamber also have been measured. Laser Doppler Anemometer (LDA) has been used to explore spatial distribution of mean axial velocity. Numerical simulation has been carried out by using computational fluid dynamic (CFD) program Adapco Star-CCM+. Detached Eddy Simulation approach and Spalart-Allmaras model have been used for calculating the flow. Results of comparison of experimental and numerical data have shown validity of used numerical method. Combination of experimental and mathematical modeling gives the possibility of obtaining detailed information representing comprehensive description of spatially complex unsteady flow with the PVC

scholarly journals The Aerodynamics of a Cornering Inverted Wing in Ground Effect

2014 ◽  
Vol 553 ◽  
pp. 205-210 ◽  
Author(s):  
James Keogh ◽  
Graham Doig ◽  
Tracie J. Barber ◽  
Sammy Diasinos
Keyword(s):  
Ground Effect ◽  
Oncoming Flow ◽  
Primary Vortex ◽  
Side Force ◽  
Straight Line ◽  
Constant Radius ◽  
Flow Curvature ◽  
Wing Geometry ◽  
Yaw Angle ◽  
Line Condition

For racing car configurations an inverted wing produces negative lift that allows increased levels of acceleration to be maintained through corners. Routine aerodynamic analysis, however, will typically be in the straight-line condition. A numerical analysis of the inverted T026 wing geometry through the curved path of a constant radius corner was conducted. The asymmetrical properties of the oncoming flow resulted in the introduction of a rolling and yawing moment along the span, as well as side-force. Yaw angle, flow curvature and a velocity gradient resulted in changes to the pressure distribution over the wing surface. Primary vortex behaviour was observed to differ significantly in both direction and structure.

scholarly journals Assessing IDDES-Based Wall-Modeled Large-Eddy Simulation (WMLES) for Separated Flows with Heat Transfer

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 246
Author(s):  
Rozie Zangeneh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Large Eddy Simulation ◽  
Skin Friction ◽  
Heat Fluxes ◽  
Separated Flows ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Isothermal Wall

The Wall-modeled Large-eddy Simulation (WMLES) methods are commonly accompanied with an underprediction of the skin friction and a deviation of the velocity profile. The widely-used Improved Delayed Detached Eddy Simulation (IDDES) method is suggested to improve the prediction of the mean skin friction when it acts as WMLES, as claimed by the original authors. However, the model tested only on flow configurations with no heat transfer. This study takes a systematic approach to assess the performance of the IDDES model for separated flows with heat transfer. Separated flows on an isothermal wall and walls with mild and intense heat fluxes are considered. For the case of the wall with heat flux, the skin friction and Stanton number are underpredicted by the IDDES model however, the underprediction is less significant for the isothermal wall case. The simulations of the cases with intense wall heat transfer reveal an interesting dependence on the heat flux level supplied; as the heat flux increases, the IDDES model declines to predict the accurate skin friction.

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