• Title/Summary/Keyword: Over-expanded fow

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Experimental and Computational Studies of FSS-RSS Phenomena in an Over-Expanded Nozzle (과팽창 노즐 내에 발생하는 FSS-RSS 현상에 관한 실험적 및 수치해석적 연구)

  • Lee, Jong-Sung;Kim, Heuy-Dong
    • Journal of the Korean Society of Visualization
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    • v.8 no.3
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    • pp.56-62
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    • 2010
  • The interaction patterns between shock wave and boundary layer in a rocket nozzle are mainly classified into two categories, FSS(Free Shock Separation) and RSS(Restricted Shock Separation), both of which are associated with the thrust characteristics as well as side loads of the engine. According to the previous investigations, strong side loads of the engine are produced during the period of transition from FSS to RSS or vice versa. The present work aims at investigating the unsteady behavior of the separation shock waves in a two-dimensional supersonic nozzle, using experimental method and CFD. Schlieren optical method was employed to visualize the time-mean and time-dependent shock motions in the nozzle. The unsteady, compressible N-S equations with SST K-$\omega$ turbulence closure were solved using a fully implicit finite volume scheme. The results obtained show the separation shock motions during the transition of the interaction pattern.