| Propeller disc wake is directly affected by shaft appendage of high speed ship, while the Vbrackets is located on shaft which is the nearest appendage to the propeller. The essential factorssuch as aerofoil profile, location and angle affect not only the ship resistance, but also thehomogeneity of propeller disc wake. Vibration and cavitation will be produced on the propellerbecause of the non-uniform wake. Therefore, propeller disc wake can be improved byoptimization of the V brackets.At present, with various kinds of numerical simulation technology rapidly developed, it ispossible to forecast the resistance and the stern wake via the CFD method. How to use thereasonable and simple method to forecasting resistance and stern wake to the preference ofmuti-project is a problem which is concerned by the ship fluid researchers.Since trim and sinkage are significant when vessels advancing forward with high speed,while normal numerical resistance prediction for vessels is under designed upright state, and theresults may not meet the engineering requirements. Based on RANS equations, multi-blockstructured grid was used, a simplified interation method was adopted in the resistance numericalcalculation of high speed vessels. By the comparison between the numerical result with modeltest data when Froude-number is between0.15and0.45, the approach is feasible to predict theresistance of high speed vessels with consideration of hull gesture. Meanwhile, the waveformand wave contour of free surface in different Froude-number was studied. The wave variationtendency at stem and stern accords with the laws. In addition, numerical simulation was adoptedto3different attack flow angles of V brackets. The simulation result of axis wake was comparedwith the model test data and the variation trend is found to be in good agreement, which provesthe reliability of the method. The conclusions could provide some reference for the preference ofappendages and propulsions. |
PDF Full Text Request