Axisymmetric turbulent boundary layers
Motivation and Background:
Turbulent ﬂows that evolve over surfaces with a strong curvature normal to the mean ﬂow exhibit turbulent boundary layers (TBL) that show different behavior than their well-known planar counterparts, like TBL of ﬂat plate or channel ﬂow.
A classical research case with a strong transverse curvature is the ﬂow along a streamwise orientated circular cylinder with a large length to diameter ratio. In ﬂows along such geometries an axisymmetric TBL develops that has a thickness much larger than the cylinder radius. In this kind of ﬂow curvature eﬀects become important, yielding to changes in TBL properties, especially on mean velocity proﬁles and turbulent statistics. In contrast to their planar counterpart, axisymmetric turbulent boundary layers or axial turbulent boundary layers (ATBL) are not well understood up to now and the body of experimental and numerical data is limited.
The candidate’s task is to simulate the axisymmetric turbulent boundary layer (ATBL) along a streamwise orientated circular cylinder with the open-source code OpenFoam and a large-eddy simulation approach (LES). Afterwards, an extensive analysis of the results is necessary.
The focus of the investigation is on:
- The performance of using different approaches to realize periodic boundary conditions in streamwise direction (“mappedPatch”, “cyclic”).
- 2. Geometry adaptions of the cylinder surface to influence the ATBL.
(The workload can be portioned so that it can be handled in Project Theses, Seminar Theses, Bachelor Theses or in a Master Thesis – the thesis can be written in English or German)
Requirements for candidates:
The applicant should have a basic-to-advanced knowledge in computational fluid dynamics (CFD) and turbulence. He/She should be familiar with the open-source code OpenFoam and should have a structured and independent approach to work. Please send your curriculum vitae and a short text to introduce yourself via Email.
Commencement of work:
From now on (15.01.2019).