LDA full field measurement of swirling flow inside container and the method to keep constant experiment Re number

Rich complicated flow problems present in swirling flow inside container,secondary flows,vortex breakdown,to name a few.However,constant working condition is necessary and important for full field measurements.The popular method to keep working condition constant used in most experimental apparatuses is to place a high-precision constant temperature water tank outside of the flow field.But it makes the measurement system complicated,and the controllable precision is limited.The method of adjusting the rotating rate dependent on measured temperature to keep Reynolds number is presented here.It is experimentally testified that the method is convenient to be used,and can keep the flow pattern at the same Reynolds number with high precision for long time.By means of the method,the full field LDA (Laser Doppler Anemometer) measurements of swirling flow inside cylindrical container are shown here,as well as measurement results of flow field inside vortex breakdown region with large number of measurement points.