Research on 3D Supersonic Cavity Flow Phenomena

Paper number

IAC-09.C2.I.11

Author

Mr. Dinghua Feng, National University of Defense Technology, China

Coauthor

Prof. Hua Li, National University of Defense Technology, China

Coauthor

Dr. Pan Sha, National University of Defense Technology, China

Coauthor

Dr. Zhengyu Tian, College of Aerospace and Materials Engineering, National University of Defense Technology, China

Year

2009

Abstract

When missile flights at high speed in aerosphere, which has optical seeker in its head side window, complex flow phenomena occurs between optical equipment and coming flow. They are real gas effect, boundary layer separation induced by shock, interaction between inviscid flow and boundary layer, et al. They will cause optical imaging and detective system’s aero-optics effects, including aero-thermal, thermal radiation, and image transmission distortion. In order to reduce thermal effect of optical window, the window of missile is usually fixed lower than its surface. This method can reduce thermal conduction coefficient. When air stream flows over the optical window at high speed, cavity flow phenomena occurs. They are shock, boundary/shear layer, turbulence, et al.

  Based on the background mentioned above, this work chose three-dimensional rectangle cavity as object, and researched the supersonic cavity flow characteristic by large-eddy simulation. Concretely, the control equation of large-eddy simulation used Favre average; the filter function was box filter; and the SGS model chosen was one-equation model used by Yoshiazwa and Horiuti. Spatial dispersion was fifth order WENO scheme, and time accuracy was fourth order used TVD Runge-Kutta method.

  Several rectangle cavities with different sizes (width W, length to depth ratio L/D) were investigated by numerical simulation. The coming stream was supersonic flow at three different Mach numbers. There are some results below:

  The supersonic cavity flow has some typical characteristic, such as leading edge shock, cavity shear layer, bump shock, and trailing edge expansion. The length to depth ratio L/D mainly affects the characteristic of supersonic cavity flow. It can directly influence the boundary/shear layer separation developed from upper cavity. The three-dimensional effect of cavity flow is highly related with width W. And the flow Mach number is also an important factor to flow characteristic. 

Abstract document

IAC-09.C2.I.11.pdf

Manuscript document

(absent)