scholarly journals The effects of viscosity on the stability of a trailing‐line vortex in compressible flow

1995 ◽  
Vol 7 (9) ◽  
pp. 2265-2270 ◽  
Author(s):  
Jillian A. K. Stott ◽  
Peter W. Duck
Keyword(s):  
Compressible Flow ◽  
Line Vortex ◽  
The Stability

scholarly journals The stability of a trailing-line vortex in compressible flow

1994 ◽  
Vol 269 ◽  
pp. 323-351 ◽  
Author(s):  
Jillian A. K. Stott ◽  
Peter W. Duck
Keyword(s):  
Mach Number ◽  
Compressible Flow ◽  
Numerical Results ◽  
Line Vortex ◽  
Mach Numbers ◽  
The Stability ◽  
Vortex Axis ◽  
Very High ◽  
High Wavenumbers

We consider the inviscid stability of the Batchelor (1964) vortex in a compressible flow. The problem is tackled numerically and also asymptotically, in the limit of large (azimuthal and streamwise) wavenumbers, together with large Mach numbers. The nature of the solution passes through different regimes as the Mach number increases, relative to the wavenumbers. At very high wavenumbers and Mach numbers, the mode which is present in the incompressible case ceases to be unstable, whilst a new ‘centre mode’ forms, whose stability characteristics are determined primarily by conditions close to the vortex axis. We find that generally the flow becomes less unstable as the Mach number increases, and that the regime of instability appears generally confined to disturbances in a direction counter to the direction of the rotation of the swirl of the vortex.Throughout the paper comparison is made between our numerical results and results obtained from the various asymptotic theories.

scholarly journals DNS and LES of the Compressible Flow Over a Delta Wing With the Symmetry-Preserving Discretization

2014 ◽  
Author(s):  
Wybe Rozema ◽  
Johan C. Kok ◽  
Roel W. C. P. Verstappen ◽  
Arthur E. P. Veldman
Keyword(s):  
Compressible Flow ◽  
Delta Wing ◽  
Region Of Interest ◽  
Simulation Models ◽  
Simulation Method ◽  
Discrete Level ◽  
Artificial Dissipation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Stability

A fourth-order accurate symmetry-preserving discretization for compressible flow is used to perform simulations of the turbulent flow over a delta wing. A symmetry-preserving discretization eliminates the non-linear convective instability by preserving conservation of kinetic energy at the discrete level. This enhances the stability of a simulation method, so that little artificial dissipation is needed for numerical stability. It is shown that simulations of the flow over a sharp-edge delta wing at Re = 50,000 with the symmetry-preserving discretization are stable without artificial dissipation in a region of interest around the delta wing. To assess the accuracy of the simulation method, results obtained on a fine computational grid are compared with results obtained on a coarser grid. Also results obtained with large-eddy simulation models and with sixth-order artificial dissipation are presented.

The stability of a trailing line vortex. Part 1. Inviscid theory

1974 ◽  
Vol 63 (4) ◽  
pp. 753-763 ◽  
Author(s):  
Martin Lessen ◽  
Pawan Jit Singh ◽  
Frederick Paillet
Keyword(s):  
Axial Velocity ◽  
Swirling Flows ◽  
Mean Velocity ◽  
Line Vortex ◽  
Swirl Velocity ◽  
Amplification Rate ◽  
The Stability ◽  
Axisymmetric Disturbances ◽  
Maximum Amplification ◽  
Swirl Parameter

The inviscid stability of swirling flows with mean velocity profiles similar to that obtained by Batchelor (1964) for a trailing vortex from an aircraft is studied with respect to infinitesimal non-axisymmetric disturbances. The flow is characterized by a swirl parameterqinvolving the ratio of the magnitude of the maximum swirl velocity to that of the maximum axial velocity. It is found that, as the swirl is continuously increased from zero, the disturbances die out quickly for a small value ofqifn= 1 (nis the azimuthal wavenumber of the Fourier disturbance of type exp{i(αx+nϕ − αct)}); but for negative values ofn, the amplification rate increases and then decreases, falling to negative values atqslightly greater than 1·5 forn= −1. The maximum amplification rate increases for increasingly negativenup ton= −6 (the highest mode investigated), and corresponds toq≃ 0·85. The applicability of these results to attempts at destabilizing vortices is briefly discussed.

ADAPTIVE FINITE ELEMENT METHODS FOR REACTIVE COMPRESSIBLE FLOW

1999 ◽  
Vol 09 (02) ◽  
pp. 211-241 ◽  
Author(s):  
ROBERT SANDBOGE
Keyword(s):  
Finite Element ◽  
Compressible Flow ◽  
Error Control ◽  
Posteriori Error ◽  
Posteriori Error Estimate ◽  
Stability Factor ◽  
Adaptive Finite Element ◽  
Adaptive Finite Element Methods ◽  
Adaptive Error Control ◽  
The Stability

We extend the adaptive streamline diffusion finite element method for compressible flow in conservation variables using P1× P0 space–time elements to include chemical reactions. The adaptive error control is based on an a posteriori error estimate involving a stability factor, which is estimated numerically. We prove for a model problem that the stability factor is bounded by a moderate constant.

A note on the effects of viscosity on the stability of a trailing-line vortex

1992 ◽  
Vol 245 (-1) ◽  
pp. 175 ◽  
Author(s):  
Peter W. Duck ◽  
Mehdi R. Khorrami
Keyword(s):  
Line Vortex ◽  
The Stability

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

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