Aerodynamics analysis around a car by CFD Hayato Suzuki
ForecastRecently, automobile industry started utilizing computersimulations like CFD(Computational Fluid Dynamics) todevelop and design car body. Previously, it prepared actual carbody model, and it evaluated car body aerodynamic characterby running wind tunnel test. To prepare actual car body modeltakes time and cost. Therefore, it tended to decrease windtunnel test and increase computer simulation. But, to re-enactactual car running had difficulty in CFD, and it had someproblems like computational result accuracy.
OutlineI use an open source simulation software which name isOpenFOAM. Here is how to simulate. First, I get the 3D data ofa car. I can not make whole car body 3D model on my own. SoI get it from web. Next, I decide a size of virtual wind tunneland position of car model in it. After that, I generate some gridsfor calculation, it is called “mesh”. Next, I set boundarycondition like inlet of air flow. After that, I execute asimulation. Finally, I display a result by visualize softwarecalled “paraView” after finished simulation. It can displaystream line, cut by X or Y or Z axis, and so on.
Motivation and Problem StatementPast CFD were a lot of simulations when a car running straightline, and low simulations when it running corner. Therefore,including cornering, I want to do simulations more real carrunning, so I tried this research. Here, I aimed to more realsimulations to actual car running by comparing the flow of theair when the car running straight line with when it runningcorner by CFD.
MethodsFirst, creating a model data. Creating 3D or 2D model by CADdata. This model will be simulation objective. Second, meshgeneration. CFD expresses calculational space in mesh. Thisnumber of mesh is very important for accuracy. A lot of meshprovide good accuracy, but it needs long calculation time. So Imust find good balance. Third, running calculation. Mylaboratory has super computer. In CFD, calculation time is verylong. So I need high spec computer. Finally,visualization. Calculation result is difficult for human eyes tounderstand.
ResultsPressure around a car. High pressure is looked front of car.