Axisymmetric turbulent boundary layers around cylinders in axial-flow

 

 

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 TBL over planar surfaces, like flat plate or channel flow, or than TBL over surfaces with moderate curvature. A classical research case with a strong transverse curvature is the flow along a streamwise oriented circular cylinder with a large length-to-diameter ratio. In flows along such geometries an axisymmetric TBL (ATBL) 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.

Task:

The candidate’s task is to simulate the axisymmetric turbulent boundary layer (ATBL) that develops 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 investigations is on:

  1. Geometry adaptions of the cylinder surface to influence the ATBL.
  2. Usage of large-eddy break-up devices (LEBU) to influence the ATBL.

Requirements for the 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.

The workload can be portioned so that it can be handled in a Project Thesis, Seminar Thesis, Bachelor Thesis or in a Master Thesis – the thesis can be written in English or German.

Betreuer:

Florian Wachter, M. Sc.

Wiss. Mitarbeiter
Raum: Raum 1.576