The Study On The Turbulent Field Synergy Model And Its Application To Drag Reduction

In the turbulent flow, the mechanical dissipation gradually increased due to various types of friction and resistance, resulting in the loss of fluid flow velocity and pressure which is all unnecessary excessive loss. Therefore, this article conducts a new study on this issue based on the field synergy theory proposed recently and completes the following major works.1) According to the incompressible turbulent flow N-S equations and continuity equation, the paper takes use of RANS and Favre Average to derived incompressible turbulent field synergy model. On the basis of the new model, we introduce the basic concepts of mechanical dissipation function and calculus of variations to derive the incompressible field synergy turbulent drag reduction formula. Meanwhile, the paper defines the concept of turbulent flow field synergy angle and fully collaborative flow field.2) This paper uses CFD methods to validate the incompressible turbulent field synergy model. We take use of incompressible water to calculate turbulent flow over a backward-facing step. The paper joins UDF procedures in consideration, changing the basic equations of fluid flow, to verify the feasibility of the mathematical model.3) According to the field synergy drag reduction model and the results of the calculation of the fully cooperative flow field, we try to find a way to optimize fluid flow and reduce the flow resistance, taking the results of the fully coordinated flow field as the ultimate optimization goal. According to the results of fully cooperative flow field, based on contrast the flow lines and the flow field synergy angle cosine, this paper propose to optimize the solid surface on the basis of near-wall flow field flow lines. We will compare viscous dissipation values before optimization with the fully collaborative flow field viscous dissipation value. The paper takes the contrastive value as a comparison reference to optimize turbulent flow over a backward-facing step.4) Finally, the comparative analysis of two optimization methods illustrates superior and rationality about the optimization of field synergy drag reduction. And the paper gives the analysis and description about the development of field synergy drag reduction in the future.