Implementation of Boundary Layer Coupling in the Tau Code

Abstract

We present a new implementation of boundary layer coupling in the TAU-Euler code. The boundary layer codes employed have previously been implemented and validated in a full potential code. TAU with boundary layer coupling has been written in a compact and user-friendly form which is ideal for redistribution. The implementation involves interpolating flow variables from the unstructured TAU grid to a structured boundary layer grid. This step and other aspects of the implementation are described in detail in the present report. Preliminary tests show good agreement with Navier-Stokes results for most (but not all) test cases. Often, these tests could be performed in less than 5% of the time than was required for Navier-Stokes simulations of the same test cases. In addition we describe a new approach for boundary layer coupling using relative surface grids. This allows us to efficiently combine boundary layer coupling with a fluid-structure coupling. Moreover, this effort has led to the development of useful tools in the domains of grid generation and postprocessing, which have proven usefull inside and outside the scope of boundary layer coupling.