Effects of adverse pressure gradient on turbulent boundary layer

Characteristics of turbulent boundary layer flows with adverse pressure gradients (APG) differ significantly from those of canonical boundary layers. In this paper we have numerically investigated the effects of APG on turbulent boundary layer. The values of pressure gradient are simulated by Clauser’s parameter ( b). By comparing the results which are obtained from mentioned equations it is known that more changes in turbulent structure are induced directly by adverse pressure gradient. Results shows that boundary layer grows faster by the effect of adverse pressure gradient, whereas if the value of adverse pressure gradient parameter ( b) is increased, growth of boundary layer can be more sensible. Also it is found that by the effects of adverse pressure gradient the turbulent intensities and turbulent shear stress are increased as compared with flat plates under the same conditions. However, the nonlinear k- e model often used in engineering applications cannot satisfy the distribution and wall-limiting behavior of the Reynolds stress component. In this case, the model used to calculate turbulent parameters is low Reynolds number turbulence models.

کلیدواژه ها:

LRN turbulence model ، boundary layer ، turbulent intensity ، turbulent shear stress ، adverse pressure gradient