キャビテーション・タンネルにおけるフローライナーを用いた制限水路影響軽減法の数値シミュレーション

抄録

The validity of CFD for flows around a ship model under strong wall effect has been tested using a SURF code developed by NMRI,computing cases in which a 6m-long full hull form is installed in the cavitation tunnel of NMRI, and comparing measured and computed wake distributions at the propeller plane. In the experiment where no flow liners were installed in the cavitation tunnel,the wake distribution became thick and strong asymmetry has occurred. In cases where flow liners were installed near the hull stern,the asymmetry in the wake distribution has disappeared and the distribution became thinner than that obtained in the towing tank. In the computation of no flow liner cases, in which only a half side was computed by assuming symmetry, the thickening of the stern boundary layer has been well simulated. In the computation with flow liners the thinning of the stern boundary layer has been well simulated, and good agreement between measurement and computation in the propeller wake has been obtained. The computed propeller wake changed according to small changes in the streamwise location of the flow liners. Thus CFD for flows under strong wall effect has been validated. Also the change in the solution convergence/oscillation behavior due to changes in the pseudo-compressibility and local Courant number parameters for the flow under strong wall effect has been discussed.