Experimental Fluid Mechanics

Abstract

The experimental flow analysis is based on conventional and up-to-date measuring techniques. Twoor three-dimensional density distributions are determined using Mach-Zehnder interferometry or holographic interferometry. Classical optical methods like the shadow, schlieren, and color schlieren technique are used to visualize flow phenomena such as shock waves, shock boundary-layer interactions, and separations. Various specifications of the particle-image velocimetry (PIV) method are applied to measure velocity distributions of internal and external flow problems. For example, using holographic PIV the three-dimensional unsteady velocity field within the cylinder of a 4-valve piston engine during intake and compression stroke could be determined. The objective of the project was the analysis of the evolution of the vortical flow field and its impact on mixing, i.e., on fuel consumption and pollution. Classical techniques to measure pressure distributions and velocities at selected characteristic points like laser-doppler anemometry (LDA) and hotwire anemometry as well as methods for flow visualization like oil pattern and smoke techniques