Numerical simulation of the effect of blockage ratio on drag measurement in water tunel test

The simulation analysis of testing model with water tunnel wall and infinite field model with free boundary is presented,which is calculated by means of numerical simulation using the popular software FLUENT.The object of this research is to make sure if the water tunnel test result about the effect of drag reduction is available to simulate and forecast the performance of infinite field case.The result indicates that the blockage ratio of the water tunnel test should not be over 25%,otherwise,the drag-reduction-effective measure demonstrated in the water tunnel test will not apply to infinite field with free boundary.In the effective range of the blockage ratio,the skin friction coefficient increases along with the increase of the blockage ratio or of the inlet velocity.