Large Eddy Simulation Of Heat Transfer And Flow Characeteristics On Flexible Wall

The application of heat transfer enhancement generally take vortex generators.However, increasing the heat transfer, it also makes flow resistance increased, so thatthe consumption of the pump power is increasing. The researches have shown thatflexible wall flow characteristics are different from the counterpart of flat wall flows.The flexible surface could enhance the surface heat transfer. However, there are fewreports of flow and heat transfer over flexible surfaces. The main objective here is tocarry on with the investigation of the influence of different flexible surface on heattransfer and flow. Special attention will be given to the analysis of flow drag reductionand heat transfer enhancement over one flexible surface.Large eddy simulation has been employed to flow and heat transfer over flexiblesurface for Re=14918. The flexible surface is obtained by imposed artificialfluctuation on the pressure of the flexible wall.A numerical investigation is conducted in a channel with one flexible wall,Computation of the flexible surface has been made for the four cases of differentamplitude to wall undulation:0.001、0.003、0.005、0.007、0.009. A detailed analysisis carried out to investigate the pressure,velocity,temperature and so on for0.005case.The results obtained indicate that the flexible surface induces much more largescale vortexs than flat wall. Nusselt number and friction coefficient change with time.This is different from solid surface cases. With increasing a from0to0.007，thetime-averaged local Nusselt number and comprehensive coefficient show an increaseof up to59.7%and87.9%, respectively. It means that the better heat transferperformance can be achieved with increasing flexible wall amplitude. The resultsshow that flexible wall with a big flexible wall amplitude could remarkably enhanceheat transfer and reduce flow drag when compared to flat wall.In addition, this paper also use the comprehensive evaluation indexes of heattransfer characteristics and flow characteristics to compare the four calculationmodels with the benchmark model. Finally found the best model.