基于小波方法的肥大船尾流大涡模拟研究

项目名称： 基于小波方法的肥大船尾流大涡模拟研究

项目编号： No.51309040

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 水利工程

项目作者： 赵勇

作者单位： 大连海事大学

项目金额： 25万元

中文摘要： 船舶湍流的复杂性主要体现在船尾流场中，尾部流场具有十分复杂的涡系结构，它们分布不均匀且不稳定，导致船舶水动力性能具有明显的非定常特征，这种情况在肥大船型中尤其明显。船尾流场的准确数值模拟，关系到螺旋桨水动力性能、噪声与振动和船体运动响应的预报精度，对螺旋桨优化设计有着十分重要的意义。雷诺平均方法不再适合非定常流场的数值模拟，有必要采用大涡模拟方法，但它受边界层内的计算量限制。本研究基于小波数学性质和湍流关键特征的互相匹配，提出小波多尺度形式的亚格子应力的新模型，并建立相应的自适应算法以提高计算效率，把它应用在肥大船型的尾流大涡数值模拟中。为快速检验并能修正模型，先应用于圆柱及椭圆柱的绕流，然后模拟某肥大型船在各种船体运动姿态下的尾流场，与试验结果比较，对误差做不确定性分析，从而给出模型和算法的可信度分析。

中文关键词： 船舶水动力；大涡模拟；小波分析；亚格子应力模型；自适应算法

英文摘要： The ship wake produces the complication of ship turbulent flow. Ship wakes contain complicated vortex structures in uniform and unstable distribution, which induces to obvious unsteady hydrodynamic performance of ships, especially full hull form.Accurate simulation of ship wake closely associates with the prediction precision of propeller's hydrodynamic performance, vibration & noise and wave induced motion of hull. Furthermore, it is highly significant to propeller's optimization design.RANS is inappropriate to simulating unsteady vortex structures. Therefore, it is necessary to employ LES although LES bears large computing load for boundary layer.This study advances a new model for the subgrid stress in wavelet multi-scale form, which is based on the match of wavelet's mathematical properties and turbulence's key physcal characters. The adaptive algorithm is proposed to promote the new model's efficiency. This method is applied to LES for simulating full hull's wakes. For quick verification and rectification, the turbulence around circle cylinder and ellipsoid is simulated with this method. Successively, this research simulates the turbulence of a full hull and this simulation is compared to experimental result and an uncertainty analysis is also carried out for model and algorithm's confidence analysis. In th

英文关键词： ship hydrodynamics；large eddy simulation；wavelet analysis；sub-grid stress model；adaptive algorithm