A shape optimisation method of a body located in adiabatic flows

Abstract

The purpose of this study is to derive an optimal shape of a body located in adiabatic flow. In this study, we use the equation of motion, the equation of continuity and the pressure–density relation derived from the Poisson’s law as the governing equation. The formulation is based on an optimal control theory in which a performance function of fluid force is taken into consideration. The performance function should be minimised satisfying the governing equations. This problem can be solved without constraints by using the adjoint equation with adjoint variables corresponding to the state equation. The performance function is defined by the drag and lift forces acting on the body. The weighted gradient method is applied as a minimisation technique, the Galerkin finite element method is used as a spatial discretisation and the implicit scheme is used as a temporal discretisation to solve the state equations. The mixed interpolation, the bubble function for velocity and the linear function for density, is employed as the interpolation. The optimal shape is obtained for a body in adiabatic flows.

Keywords:

• shape optimisation
• optimal control theory
• finite element method
• weighted gradient method
• fluid force
• adiabatic flow

Acknowledgements

This paper is written with the help of Yu Samizo and Ryosuke Sato, students of Chuo University. Computation is carried out using Dospara Computer Prime 557848.