Bremen 2017 – wissenschaftliches Programm
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K: Fachverband Kurzzeitphysik
K 2: Laseranwendungen und Laserstrahlwechselwirkung I
K 2.4: Vortrag
Dienstag, 14. März 2017, 09:45–10:05, GW2 B2890
Unsteady micro shock waves induced by time-dependent driver — •Yun Kai1,2, Walter Garen1, Theodor Schlegel1, and Ulrich Teubner1,2 — 1Hochschule Emden/Leer, Institute for Laser and Optics — 2Carl von Ossietzky University of Oldenburg, Institute of Physics
Shock wave is a typical phenomenon in supersonic fluid mechanics. One can encounter shock waves in many different fields of study such as aerospace technologies, ocular surgery, drug delivery etc. Since recent years, shock waves at micro scale have gained great attention, because they deviate from classical theories which govern the macroscopic shock waves. New experimental methods to generate shock waves are needed, since conventional diaphragm technology fails at micro scale. In current studies, high power lasers and high-speed valves are applied in these new methods. Different from a conventionally generated shock wave, a high power laser generated shock wave is unsteady, which means the flow properties are time-dependent in a shock fixed reference frame. This is a result of the time-dependent driver with varying pressure, temperature and density. In this work, a similar unsteady shock wave is simulated by using a high-speed magnetic valve, which can operate in a pulsed mode. Through the variation of the gas pulse length, one can investigate the influence of the driver presser P4(t) on the shock wave Mach number M1. This work provides a unique view of one of the smallest shock waves available in the scientific community. Both experimental and theoretical findings will be presented.This project is funded DFG.