Stability of an accelerated shear layer

Journal Article · Tue Jul 01 04:00:00 EDT 1986 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.865558· OSTI ID:5797492

Mjolsness, R C; Ruppel, H M

A fluid shear layer with free boundary conditions is subject to a Kelvin--Helmholtz-like instability. When the shear layer is accelerated by a difference in applied pressures it is also subject to a Rayleigh--Taylor-like instability. The combined action of these instabilities leads to at most one unstable mode at each wavelength, whose behavior depends in detail on fluid parameters, the fluid acceleration and the perturbation wavelength. Typically, at longest wavelengths the instability is essentially of Rayleigh--Taylor form; its behavior resembles the Kelvin--Helmholtz-like mode at shorter wavelengths, near the thickness of the shear layer, cutting off when the Kelvin--Helmholtz-like mode does. At still shorter wavelengths, the shear layer is subject to a Rayleigh--Taylor-like instability. Careful control of fluid parameters could place the most unstable wavelength for Rayleigh--Taylor instability, calculated from viscous theory, in the range of wavelengths where the accelerated shear layer has no unstable mode. However, this may be difficult to achieve in practice. If this can be realized, the most unstable growth rate may be reduced by about an order of magnitude by the presence of shear.

• Research Organization: Theoretical Division, Group T-3, University of California, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 5797492
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:7; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

640420* -- Fluid Physics-- Properties & Structure of Fluids-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACCELERATION
BOUNDARY CONDITIONS
FLUIDS
HELMHOLTZ INSTABILITY
INSTABILITY
LAYERS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PRESSURE EFFECTS
PRESSURE GRADIENTS
RAYLEIGH-TAYLOR INSTABILITY
SHEAR
STABILITY