use of a central-difference scheme in the time direction yields non-physical transient solutions as a consequence of pressure waves travelling backwards in time. Therefore, an upwind formulation is provided and validated against one-dimensional test cases: a semi-infinite piston and a finite piston with a sharp change in direction. Also a hybrid formulation is given and several two-dimensional unsteady aerodynamics cases are computed with all three formulations and compared, demonstrating that the use of an upwind time stencil yields more representative physical solutions and improves the rate of convergence. In particular, the following problems are presented: a pitching NACA-0012 (periodic); a simple flap deflection; a spoiler deployment; a full landing case with a combination of slat, flap and spoiler deployments along with ground effect; and a case where aerofoils fly in opposite directions at subsonic and supersonic speeds.
|Title of host publication||23rd AIAA Computational Fluid Dynamics Conference|
|Publisher||American Institute of Aeronautics and Astronautics Inc. (AIAA)|
|Number of pages||26|
|Publication status||Published - 9 Jun 2017|
19 Mar 2019
Student thesis: Doctoral Thesis › Doctor of Philosophy (PhD)File