Convegni ATI - Accesso riservato soci CTI

Autore: A. Dadone, B. Grossman

Collana: CA - 52 - Cernobbio 1997

Note:
A new formulation for the robust and efficient design optimization of fluid flow problems is presented. The methodology has three essential ingredients. First, the use of highly accurate flow solvers vhich need additional modification. Second, accurate and efficient design sensitivities are obtained using a discrete adjoint formulation. The adjoint problem is based on a dissipative flow solver in order to obtain robust sensitivity derivatives in the presence of noise or other non-smoothness associated with objective functions on many high-speed flow problems. The adjoint formulation permits the evaluation of accurate sensitivity derivatives nearly independent of the number of design variables. The third ingredient of the procedure involves what we term a progressive optimization, whereby a sequence of operations, containing a partially converged flow solution, followed by an adjoint solution followed by an optimization step is performed. Furthermore, the progressive optimization involves the use of progressively finer grids. This approach has been tested on several two-dimensional diffuser, nozzle and channel flow design problems in transonic and supersonic flow. The methodology is shown to be accurate, robust and highly efficient, with a converged design optimization produced in no more than the amount of computational work to perform from two to four flow analyses and depending on the considered test case.