There are several possible situations where flow around a vehicle passing another vehicle or infrastructure such as a tunnel or a platform is of interest. This kind of application requires an unsteady simulation technique which can simulate moving vehicles. Our solution is to use a combination of moving and deforming computational grids in combination with an appropriate hybrid turbulence approach such as DES or an URANS simulation (depending on the character of the problem).
An example of our solution of the problem of two high-speed trains passing each other is shown in the following figure: