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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

SLIDE 1

Production of diverging and converging spherical shock waves and eccentric interaction of converging shock waves with cylindrical interfaces

Shock Wave Research Center, I.F.S., Tohoku University, Sendai, Japan S.H.R. Hosseini and K. Takayama

The 8th International Workshop on the Physics of Compressible Turbulent Mixing

Dec. 9-14, 2001, Pasadena, CA

SLIDE 2

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

SLIDE 3

Aspheric spherical test section

Shock Wave Research Center, I. F. S., Tohoku University

SLIDE 4

Front view of the aspheric spherical test section

Shock Wave Research Center, I. F. S., Tohoku University

SLIDE 5

Laser light rays in the aspheric test section

48.2 φ φ φ φ150 φ φ φ φ203.3 Laser light 270 Pressure transducer

Shock Wave Research Center, I. F. S., Tohoku University

SLIDE 6

Double exposure holographic interferometric optical set-up

Film holder Parabolic mirror d=1000 mm, f=8 m M Ruby laser d=1000mm, f=8 m Parabolic mirror 5:5 Beam splitter L Power Aspheric test section M M M L L L Optical fiber Pulse generator Delay circuit Nd:YAG laser Digital memory From pressure transducers

Shock Wave Research Center, I. F. S., Tohoku University

SLIDE 7

Structure of vertical diaphragmless shock tube

Cht Ch1Ch2 Test section Low pressure channel High pressure chamber Auxiliary pressure chamber 1145 2670 Leak section 300 210 92 Rubber membrane φ φ φ φ 310 Paux. High pressure chamber 30 φ φ φ φ 230 10 Vertical channel Inner-wall Out-wall Ch3 7 φ φ φ φ 130 Glass window Mirror 5 6 10 10 φ φ φ φ 230 4 Test gas

Shock Wave Research Center, I. F. S., Tohoku University

SLIDE 8

Double exposure holographic interferometry

M Film holder Parabolic mirror d=300 mm, f=3 m L L M Ruby laser M M M d=500mm, f=5 m Parabolic mirror L 6:4 Beam splitter M

B. S.

M M M M M Power Delay Digital memory L Ch1 Ch2 Cht

Shock Wave Research Center, I. F. S., Tohoku University

SLIDE 9

Test section with cylindrical bubble

Ms Light or heavy gas Ms

､P

Interface (soap bubble cylinder) Air at room temperature Window Mirror 12.1 12 25 37.5 50 Ch3 Ch8 Ch7

4 5 6

Shock Wave Research Center, I. F. S., Tohoku University

SLIDE 10

P / P0

1 2 3 4 5 6 0.88 0.96 1.04 1.12 1.2 SF6 50 mm dia. bubble Ch1 Ch2 Ch4 Ch5 Ch6 Ch7 Ch8 Ch3 Time (ms)

Shock Wave Research Center, I. F. S., Tohoku University

Pressure histories at the test section for eccentric interaction of cylindrical shock wave with cylindrical SF6 bubble, Msi=1.18, P0=101.13 kPa

SLIDE 11

Msi=1.18 in air, P0=100.3 kPa, DSF6=50mm

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

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

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

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

SLIDE 15

Shock Wave Research Center, I. F. S., Tohoku University

Large scale vortex

SLIDE 16

Vj (m/s) Time variation of average SF6 jet velocity in air

Shock Wave Research Center, I. F. S., Tohoku University

10 20 30 40 50 60 70 200 400 600 800 1000 1200

Time (µs)

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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 SF6 heavy gas bubble resulted a strong SF6 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