Actively translating a rear diffuser device for the aerodynamic drag reduction of a passenger car

Impact of ground and wheel boundary conditions on numerical simulation of the high-speed train aerodynamic performance

“…In the DES turbulence model, an unsteady RANS model is used in the near wall regions and Large Eddy Simulation in the region where large turbulence scales play a dominant role. A realizable k-ε model is chosen in the vicinity of walls because it is known to provide superior performance for flows involving rotation, boundary layers with adverse pressure gradients, separation and recirculation (Kang et al, 2012;Guilmineau et al, 2011). In the simulations of this paper, the Finite Volume Method (FVM) based on cell centers was adopted for the discretization of the governing equations.…”

Predicting self-pollution inside school buses using a CFD and multi-zone coupled model

“…A uniform incoming flow of the bus driving speed was introduced into the modeling domain from the inlet perpendicularly. The left, right, ground, and top of the modeling domain were regarded as "moving wall" with a no-slip condition corresponding to the bus driving speed (Chan et al, 2008;Kang et al, 2012;Uhrner et al, 2007). For the outlet, the boundary condition was set to pressure outlet with the reference pressure of 0 Pa. On the surface of the bus, no-slip, adiabatic, and inert wall conditions were applied.…”

Automotive underbody diffuser for battery thermal management

“…For example, a study reported a general design guideline for the optimal dimensions and geometry of an automotive underbody diffuser for low drag and high downforce using an Ahmed body (Jowsey and Passmore, 2010). On the other hand, the design of an active diffuser that changes shape depending on velocity, results in an improvement of up to 4% drag reduction on a specific Hyundai model (Kang et al, 2011). Further underbody aerodynamic research involves improving the understanding of features such as the flow in wheelhouses and around the tires (Regert and Lajos, 2007), and optimising the Ahmed body (Beaudoin and Aider, 2008).…”