Master/Project thesis: Flat plate boundary layer measurements in wind tunnel
Background:
A uniform fluid flow over a solid surface develops a boundary layer because of the viscous forces very close to the wall. Due to the instabilities present on the surface, a smooth laminar boundary layer transitions into turbulent boundary layer at sufficient enough Reynolds number. To determine the growth of the boundary layer and turbulence levels, often small-scale experiments are conducted in a wind tunnel. The wind tunnel at Institute of Fluid Mechancis (LSTM) is a Göttingen-type canal with an open measuring section designed for external flows over bluff bodies with an ability to experiment on flat plate boundary layers. The nozzle follows the calming section with a contraction ratio of 5:1. The wind tunnel is powered by two axial fans with an installed output of 2 x 200 kW. A cross section of 1.86m x 1.4m with a test section of 2.2m with a speed range of 0-60m/s at the center of wind tunnel. The wind tunnel has been characterized and Ahmed body measurements were conducted by Prof. Dr. Stefan Becker in 2009. The proposed project is to measure the wind tunnel characteristics, velocity variation across cross-section and downstream, variation of turbulence intensity using either of the experimental techniques, PIV, hot-wire anemometry and LDA. Furthermore, determining the boundary layer thickness on a flat plate placed in the wind tunnel.
Specific tasks:
- Literature study on the topics of turbulence boundary layers, types of wind tunnels and their characteristics, experimental techniques like PIV, LDA, or Hot-wire anemometry
- Preliminary simulation of the LSTM wind tunnel using ANSYS FLUENT/STARCCM+ or equivalent commercial software
- Learning and setting up the wind tunnel, hot-wire anemometry, PIV, LDA.
- Setting up the flat plate in the wind tunnel for the boundary layer measurements
- Data analysis and reporting of the results
Requirements:
- Experience and interest in wind tunnel experiments and turbulence
- Data analysis experience in Python and/or Matlab
- Independence working style
Starting date: immediately
Supervisor:
