Acceleration of convergence to a periodic steady state in turbomachinery flows

Abstract

This paper present s at echnique usedt o accelerat et he convergence ofunst eady calculat ions oft ime-periodic flowst o a periodic st eady st at e. The basis oft he procedure is t e use of t e discret e Fouriert sform int ime, and is similart ot he harmonic balance proceduret hat has been pursued by Hallet . al. Thet echnique is amenablet o parallel processing, and convergence accelerat t echniques such as mult grid and implicit residual averaging. The comput at ional e#ciency oft his met hod is compared wit h dual t imest epping algorit hms. Sample calculat ions are provided, and a comparison bet ween solutI s wit varying t mporal resolutI is present d. The result show tat t e comput al e#ciency of t e harmonic balance t chnique is largely a funct of t et emporal resolut ion. Init ial experiment s confirmt he promise oft he harmonic balance met hodt o achieve significant reduct ions in comput at ional cost .