Motivation

Due to enormous advances in the field of digital camera, laser and LED technologies for spatially and temporally highly-resolved image acquisition on the one hand and the increased performance of computers and GPU clusters for digital image processing on the other hand, optical measurement techniques are in a rapid upswing and are increasingly replacing classic, sensor-based measurement techniques. In the lecture the theoretical, optical and technical basics, as well as current further developments and applications of image based measurement methods in the areas of aerodynamics, fluid mechanics, and aero-elasticity, as well as partly in aeroacoustics will be presented. In addition to methods that aim at the acquisition of aero-dynamically and -elastically relevant measurement variables such as the distribution of pressure, deformation, temperature or wall shear stress on model surfaces, optical methods for the planar and volumetric measurements of scalar quantities in flows, such as density, concentration or temperature are discussed. However, the greater part of the lecture will deal with the theory, application and evaluation of particle-based measurement methods for the planar and volumetric determination of instantaneous and time-resolved velocity, acceleration and pressure fields in unsteady flows, as well as with the possibilities of the subsequent data assimilation and analysis tools.

Content

The students will learn the (laser-) optical and electronic basics as well as suitable digital image processing and evaluation methods for various 2D- and 3D image based measurement- and visualization methods (e.g. PIV, LPT, LIF, PSP, TSP, BOS, DIC etc.) for aerodynamics. Through relevant applications to unsteady and rotational flows and on surfaces of bodies immersed in such flows, the students will get to know the limits (systematic and signal-to-noise ratio-related measurement uncertainties) and possibilities of different optical (non-intrusive) measurement techniques. Equipped with this knowledge, the students learn the use of (statistical) analysis tools that can be applied to the experimentally achieved instantaneous or time-resolved planar or volumetric flow field data from industrial flow facilities or wind- and water tunnels in order to achieve a deeper understanding of the investigated flow properties and related (dynamical) forces and moments. The quantitative flow measurement data and their analysis should in turn enable the students to directly relate to the underlying Navier-Stokes equations, to validation procedures for (U)RANS and other CFD methods, to different models and dynamics of vortical flow structures, to aero-elastically coupled fluid-structure interactions or to the field of aero-acoustics.

Inscription

Kurs: 13518 Image based measurement techniques for fluid mechanics

Dates

Lecture

Thursday 13:45 - 17:00, bi-weekly (B-week).

The first lecture starts on 11.4.2024.

Practice

Thursday 13:45 - 17:00, bi-weekly (A-week).

The first practice starts on 18.4.2024.