Advances in the understanding of compressible turbulent boundary layers

Compared to their incompressible counterparts, compressible turbulent boundary layers have not been investigated as extensively and thus numerous, partly fundamental aspects of their description have not been clarified satisfactorily to date. Essentially, the sheer size of the parameter space alone can be considered as one of the main difficulties in the description of compressible flows. Essentially, this work represents a summarizing overview of the research conducted by the author and his working group in recent years in the topic of compressible turbulent boundary layers by means of direct numerical simulation. These studies are characterized by a high degree of systematics and thus extend the current state of knowledge in various points. Broadly speaking, the research questions addressed can be assigned to mainly three topics. In the first topic, the aspects discussed are aimed at broadening our knowledge about the comparability of compressible turbulent boundary layers with different Mach numbers and wall temperatures. The second focus is mainly devoted to the influence of pressure gradients at near adiabatic wall temperatures, while the third focus discusses the combined influence of pressure gradients and strongly diabatic wall conditions. Accordingly, this work can be understood as a pointed summary of previous findings, current research and a (long-term) outlook on future research topics of the working group led by the author.