Numerical Simulation Of Low Speed Wind Tunnel And CFD-based Optimal Design

Wind Tunnel-Circulating Water Channel(CWC) is one of important facilities inState Key Laboratory of Ocean Engineering, Shanghai Jiaotong University. CWC cansimulate different environment conditions, such as wind, wave, stratified flow, predictthe hydrodynamic performance of naval architecture and ocean structure. CWC is madeup of low-speed wind tunnel and circulating water channel. The wind tunnel consiststwo test sections. Due to the unique features and difficulties of the plan, CFD methodis employed to explore in design.The design of wind tunnel depends on empirical formula at the present stage. Asthe development of CFD, the numeric simulation results are compared with the testresults to explain flow mechanism. The research about Computational WindEngineering also has made great progress. In spite of this, there is little case in whichCFD is used for wind tunnel design. Account of all factors, simulating the flow fieldin wind tunnel accurately is significant, even though the design can’t completelydepend on the simulation results.In this paper, further exploration which is based on the research of the domesticand overseas scholars is completed. CFD method is employed to simulate the viscousflow field in the entire wind tunnel for the first time. To obtain accurate and detailresults, the damping, protective nets and physical fan are included. The computedvolume flow rate approximates the designed value by the empirical design, while thepressure losses are partly in agreement with the computed results of empiricalformulas. The numerical result reproduces the flow phenomena, like flow separationsso as to make it clear how to improve the performance of wind tunnel. The changeof flow field which is caused by non-axiality in the wind tunnel is investigated, theresults show that small change of axiality has little effect on its flow characteristics.The research about that body-force replace fan to simulate the flow condition infan section is taking up. The results show body-force can reduce the complexity of fansection after confirming the parameters. In addition, body-force has unique advantagein the study of loss coefficient. It can offer designers more accurate information.The flow quality of test section in wind tunnel is a key indicator. According to design feature, the flow field in big test section is more important. To enhance theuniformity of the flow in big test section, after simplification, FLUENT and GAMBITintegrated by optimization software iSIGHT is used to optimize the number ofseparators, dimension of stable segment and guide vanes. The results show itseffectiveness.CFD simulation has enlightening significances in wind tunnel aerodynamicdesign. In next stage, simulating accuracy will improve. Optimizing reliability andpractical values will enhance.