The DLR TAU code is ...
... actually not one code but a modern software system for the prediction of viscous and inviscid flows about complex geometries from the low subsonic to the hypersonic flow regime, employing hybrid unstructured grids. The system, in the following just called TAU, is composed of a number of modules and libraries to allow easier development, maintenance and reuse of the code or parts of it. The different modules of TAU, briefly described in the following, can both be used as stand-alone tools with corresponding file I/O or within a Python scripting framework which allows also for inter-module communication without file-I/O, i.e. using common memory allocation.
One of the important features of the TAU-Code is its high efficiency on parallel computers and its optimization for cache processors through specific edge colouring procedures. Parallelization is based on domain decomposition and the message passing concept using MPI. All modules of the system described in the following are capable of running in parallel.
While TAU is mainly used for complex aircraft-type configurations (including coupling to structure and flight mechanics codes) there exist also extensions which allow the simulation of re-entry flows, i.e. chemical reactions of air (or other gases) can be taken into account.
While TAU comprises modules for grid modification, namely the adaptation and the deformation module, it does not include grid generation. TAU can be used with both (block-) structured and hybrid unstructured grids composed of hexahedrons, prisms, tetrahedrons and pyramids. The first two element types are usually used in semi-structured layers above surfaces allowing for a better resolution of boundary layers. Tetrahedrons are used to fill the computational domain in a flexible way, allowing for local refinement without hanging nodes while the pyramids are needed for the transition between elements with quadrilateral faces and elements with triangular faces.
The description  of some of the TAU modules can be found by clicking on the following headings: