Vehicle Dynamics Simulation

Objective: To reduce the draft zone leading to design modification after “B” pillar.

a) First two simplified car models (dimensions reference to a stock car) has been generated in Solidworks one behind other. Using Gambit 3D mesh has been generated for 10x X 8x X 5x control volume. The appropriate boundary condition has been assigned to respective surfaces and simulation has been performed using k-epsilon turbulent model. Pressure has been checked for trailing car and turbulent intensity has been checked for leading car.

Based on above analysis, variation modification has been checked with simulation. The model with lowest turbulent intensity and highest pressure on trailing car has been chosen.

The same exercise has been done again to perform the simulation.

Outcome: The pressure on the trailing car has been increased and the turbulent intensity has been reduced for the leading car. 

Defining first the domain of the flow by means of enclosure and giving named selections inlet, outlet, walls in ICEM CFD then part mesh set up, compute mesh, compute prams, creating layers. In CFX pre-processor applying boundary conditions (Mass, Momentum conversation+turbulence, Energy conservation + turbulence term, Law of the wall,)with Turbulence K-e model (and dissipation), RANS, RSM, LES model with inlet velocity and other related parameters. In post processor selecting the required boundary condition to analyze flow over the car.

Turbulence is visible over the structure and looked not very much appealing as rounded swirls. If we could understand this phenomenon many of the commotions would have needed much less explanation. The reason could be the limitation in iterations and the nature of the problem requires the more conceptual approach based on the concrete research.