This paper is concerned with the numerical modeling of the ﬂow behind the base of a generic rocket. The DLR TAU code is ﬁrst applied in a design study about the support of the model in the hypersonic environment. At the given circumstances a slanted support shows no advantage over an orthogonal design. The investigation then focuses on two conﬁgurations, related to hypersonic and to subsonic experiments conducted in Cologne and Aachen respectively. The applicability tests of different turbulence models are started on the level of two equation models calculating the steady state solution of the Reynolds averaged Navier Stokes equations. It will be continued with the calculation of unsteady ﬂow ﬁelds around these simpliﬁed conﬁgurations as well as conﬁgurations with increasing complexity. All used models - the original Wilcox k-ω, the Menter SST and the EARSM formulation - predict an asymmetric base ﬂow in both cases caused by the support of the models. A ﬁrst comparison with preliminary experimental results indicates a preference for the SST and EARSM results over the results from the older k-ω model.