Discharge convective instability as modifier of nonlinear hydrodynamic spectrum

TL;DR

This paper investigates how discharge sources modify the nonlinear hydrodynamic spectrum in supersonic flows, identifying stages of discharge and factors influencing pulsation frequencies through theoretical and experimental analysis.

Contribution

It introduces a new understanding of how discharge stages and parameters influence pressure fluctuation spectra in supersonic flows.

Findings

Discharge stages are identified as sliding and still stages.

Stage transition is caused by convective instability.

Hydrodynamic resistance and cathode electric field are key frequency modifiers.

Abstract

Discharge source is considered as modifier of flow hydrodynamic spectrum. Characteristic frequency of nonlinear spectrum and spectrum power were determined under conditions of arc sliding discharge in supersonic flow. Two stages of discharge were defined: sliding stage and still stage. It was found that stage transition occurs due to convective instability of discharge. Fraction of sliding stage in overall discharge duration is determined by averaged current that is general stable discharge parameter. This phenomenon gives opportunity to control power of pressure fluctuations spectrum. Theoretical insight of field and hydrodynamic factors influencing on pulsations frequency was achieved. Hydrodynamic resistance of discharge region and holding cathode electric field turned out to be basic factors of frequency modification. Corresponding experimental verification was taken. Basic frequency law was determined for several discharge regimes.