Implementation of a spatial/temporal method for simulating turbulent wake

Submarines leave a hydrodynamic turbulent signature trace in its wake that can be detected with different sensors. Since the turbulence is very long- lived it is computationally expensive to numerically simulate both the wake- generator (submarine) and its whole wake, therefore another method must be used. One such method for simulating the turbulent fluctuations consists of splitting the problem into two parts: one spatial simulation of the wake genera- tor, and one temporal simulation of the wake region. The temporal simulation uses cyclic boundary conditions between the inlet and outlet, so that the de- velopment in time can be interpreted as a displacement downstream, and is initiated from a given timestep in the spatial simulation. This report explores the capabilities of this type of temporal simulation method. The method is evaluated for a sphere at Reynolds number ReD = 8600. The sphere was chosen as the wake generator due to the avability of reference data in the literature to validate the method. The near-wake characteristics are compared to DNS-simulation data and the far-wake characteristics are com- pared to data from wind tunnel measurements. Various meshes, domain sizes, and boundary conditions are also tested, and recommendations on how the computations should be set up are given. The results show that the method can be used for computing the fluctuation profiles far downstream of an object.