Production of diverging and converging spherical shock waves and - PowerPoint PPT Presentation

The 8th International Workshop on the Physics of Compressible Turbulent Mixing Dec. 9-14, 2001, Pasadena, CA Production of diverging and converging spherical shock waves and eccentric interaction of converging shock waves with cylindrical interfaces S.H.R. Hosseini and K. Takayama Shock Wave Research Center, I.F.S., Tohoku University, Sendai, Japan

Introduction • Upon focusing of spherical or cylindrical shock waves, high pressures and temperatures created at the center of convergence and have been used for various scientific and industrial applications. • It is not necessarily easy in laboratories to produce uniformly converging shock waves. • Applications of R-M instability appearing in converging spherical and cylindrical geometries, such as inertial confinement fusion, supersonic combustion, and astrophysics, made it of considerable interest. • In the present research, results of recent experiment of R-M instability will be reported. Shock Wave Research Center, I. F. S., Tohoku University

Aspheric spherical test section Shock Wave Research Center, I. F. S., Tohoku University

Front view of the aspheric spherical test section Shock Wave Research Center, I. F. S., Tohoku University

Laser light rays in the aspheric test section Pressure transducer Laser light φ 203.3 φ 150 φ φ φ φ φ φ 48.2 270 Shock Wave Research Center, I. F. S., Tohoku University

Double exposure holographic interferometric optical set-up L L M M Film holder L Parabolic mirror d=1000mm, f=8 m Aspheric test section Parabolic mirror L Ruby laser Power d=1000 mm, f=8 m 5:5 Beam splitter M M Optical fiber From pressure transducers Pulse Delay Nd:YAG generator Digital memory circuit laser Shock Wave Research Center, I. F. S., Tohoku University

Structure of vertical diaphragmless shock tube 7 4 5 92 Glass window 6 10 Ch3 Ch1Ch2 Test section Test gas 210 φ φ φ φ 130 300 Mirror 10 Cht φ φ φ φ 230 Out-wall Low pressure channel φ φ φ φ Vertical channel 310 2670 φ φ φ φ 230 High pressure chamber 10 Inner-wall 30 Rubber membrane High pressure Paux. 1145 chamber Leak section Auxiliary pressure chamber Shock Wave Research Center, I. F. S., Tohoku University

Double exposure holographic interferometry M M M M M M Parabolic mirror M Film holder d=500mm, f=5 m L L M L M M L B. S. Parabolic mirror M Ch2 6:4 Beam splitter d=300 mm, f=3 m Ch1 Ruby laser Cht Power Digital memory Delay Shock Wave Research Center, I. F. S., Tohoku University

Test section with cylindrical bubble 50 Ch 7 37.5 25 12.1 12 Window Ch 8 6 5 4 Ch 3 Ms Mirror Light or heavy gas Ms ､ P � Air at Interface room temperature (soap bubble cylinder) Shock Wave Research Center, I. F. S., Tohoku University

Pressure histories at the test section for eccentric interaction of cylindrical shock wave with cylindrical SF 6 bubble, Ms i =1.18, P 0 =101.13 kPa Ch1 Ch2 SF 6 50 mm dia. bubble Ch3 6 Ch4 Ch5 5 Ch6 Ch7 Ch8 4 P / P 0 3 2 1 0.88 0.96 1.04 1.12 1.2 Time (ms) Shock Wave Research Center, I. F. S., Tohoku University

Ms i =1.18 in air, P 0 =100.3 kPa, D SF 6 =50mm Reflected SW Converging SW Initial interface position Interface Shock Wave Research Center, I. F. S., Tohoku University

Reflected SW Transmitted SW Converging SW Initial interface position Perturbed interface Shock Wave Research Center, I. F. S., Tohoku University

Reflected SW Transmitted SW Diverging SW Initial interface position Perturbed interface Shock Wave Research Center, I. F. S., Tohoku University

Reflected SW Diverging SW Transmitted SW focusing Initial interface position Perturbed interface Shock Wave Research Center, I. F. S., Tohoku University

Shock Wave Research Center, I. F. S., Tohoku University Large scale vortex

Time variation of average SF 6 jet velocity in air 70 60 50 V j (m/s) 40 30 20 10 200 400 600 800 1000 1200 Time ( µ s) Shock Wave Research Center, I. F. S., Tohoku University

Summary 1) Converging spherical shock waves and their interaction with micro-explosive product gases were investigated by using a spherical transparent test section. 2) Using double exposure holographic interferometry, the interactions of converging shock waves with light/heavy cylindrical gaseous interface were quantitatively visualized. A relatively strong secondary shock wave focusing in SF 6 heavy gas bubble resulted a strong SF 6 jet in air, which made the final distortion of the bubbles to be different from planar shock wave loading. Shock Wave Research Center, I. F. S., Tohoku University