Linear temporal stability analysis on non-parallel free cross sheared flow with a primary hyperbolic velocity and an orthogonal Bickley jet velocity

2021 ◽  
Vol 33 (12) ◽  
pp. 124101
Author(s):  
Yuan Xiao ◽  
Wenxian Lin
Keyword(s):  
Stability Analysis ◽  
Temporal Stability ◽  
Sheared Flow ◽  
Jet Velocity

Spatial Stability Analysis of a Flap Side Edge Vortex

2005 ◽  
Vol 4 (1-2) ◽  
pp. 37-47
Author(s):  
Jean-Philippe Brazier ◽  
Frédéric Moens ◽  
Philippe Bardoux
Keyword(s):  
Stability Analysis ◽  
Temporal Stability ◽  
Low Frequency ◽  
Aerodynamic Noise ◽  
Navier Stokes ◽  
Mean Flow ◽  
Side Edge ◽  
Amplification Rate ◽  
Edge Vortex ◽  
Flap Deflection

The flap side edge vortex is suspected to contribute to aerodynamic noise generation. Using a temporal stability analysis, Khorrami and Singer have shown that unstable modes could exist in this vortex. Due to the convective nature of this instability, a spatial analysis is more suitable. This is the subject of the present work. The mean flow past a 2D wing with a half-span flap has been computed with a steady 3D Navier-Stokes code. Then, local linear stability calculations are performed in several planes perpendicular to the vortex axis. The vortex is assumed axisymmetric and modelled with Batchelor's analytical vortex. Using Gaster's relation, the spatial amplification rate is calculated, giving by integration the relative amplitude of the fluctuations. Some low-frequency fluctuations are seen to be preferentially amplified by the vortex, but the amplifications remain small, so that this mechanism alone should not produce important noise in this particular configuration, where the flap deflection angle is moderate.

On the applicability of temporal stability analysis to raingauge network design

2019 ◽  
Vol 64 (12) ◽  
pp. 1424-1438
Author(s):  
Renato Morbidelli ◽  
Carla Saltalippi ◽  
Alessia Flammini ◽  
Marco Cifrodelli ◽  
Jacopo Dari ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Network Design ◽  
Temporal Stability
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