What is it about?
When you throttle a hypersonic inlet, the buzz-frequency varies. Is there a simple way to predict this buzz frequency for a variety of inlet mach number and throttling conditions? There is a way, and in this paper, we have tried to explain.
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Why is it important?
Current hypersonic vehicle design needs the characteristic large-scale frequency to develop a proper structural frame-work. The findings from the present study will help in arriving at it easily through simple correlations.
Read the Original
This page is a summary of: On the unsteady throttling dynamics and scaling analysis in a typical hypersonic inlet–isolator flow, Physics of Fluids, December 2020, American Institute of Physics, DOI: 10.1063/5.0032740.
You can read the full text:
Hypersonic intake unsteadiness
[Multimedia View] Typical instantaneous contour plots of the Mach number observed at an arbitrary time step during the simulation of different throttling ratios. A steady flow field is observed up to 0 ≤ ζ ≤ 0.2 and an unsteady flow field is seen for 0.3 ≤ ζ ≤ 0.7. Key flow features: 1—shock from ramp-1, 2—shock from ramp-2, 3—shock from ramp-3, 4—shock-wave boundary layer interaction (SWBLI) on the cowl wall, 5—SWBLI on the ramp wall, 6—secondary SWBLI inside the isolator, 7—throttling plug induced shock, 8—choking induced by the throttling plug, 9—formation of unsteady pseudo shock/shock train, 10—increasing throttling plug height, and 11—the sinuous upstream motion of the pseudo shock/shock train. https://doi.org/10.1063/5.0032740.1 On the unsteady throttling dynamics and scaling analysis in a typical hypersonic inlet–isolator flow Physics of Fluids 32, 126104 (2020); https://doi.org/10.1063/5.0032740
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