Accession Number:

ADA278761

Title:

Experimental Studies of Very-High Mach Number Hydrodynamics

Descriptive Note:

Interim rept.

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s):

• Grun, Jacob
• Manka, Charles
• Ripin, Barrett
• Buckingham, Alfred
• Kohlberg, Ira

Report Date:

1994-02-14

Pagination or Media Count:

82.0

Abstract:

We present results of experiments on very-high Mach number 100 shocks and very-high Mach number and Reynolds number 100, 106 turbulence. Such high Mach number hydrodynamics are initiated with a powerful laser pulse driver. We show that shocks created with a laser driver follow the Taylor-Sedov self-similar solution and scale via the Sachs scaling law just like shocks created by more traditional methods. In one experiment we examined laser- produced-shock solid-surface interactions and observed expected phenomena such as Marsh stems and triple points, and also measured a new phenomenon termed a blast wave decursor. In second experiment we found that shocks become unstable if they propagate through a gas which has a low adiabatic index and we measured the growth rate of the instability. In a third experiment we have shown that a high Mach number shock dramatically enhances the structure of a turbulent field through which it passes and that the shock is itself badly distorted. This result is unexpected since common wisdom has it that high Mach number shocks would self-heal as they pass through a turbulent field. Turbulence, Shock.

Descriptors:

• *SHOCK WAVES
• *PULSED LASERS
• *MACH NUMBER
• *HYDRODYNAMICS
• INTERACTIONS
• BLAST WAVES
• INSTABILITY
• REYNOLDS NUMBER
• SURFACES
• PULSES
• LASERS
• TURBULENCE
• PLASMAS(PHYSICS)

Subject Categories:

• Lasers and Masers
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE