物体附加质量的一种改进算法  

An improved algorithm for the computation of added mass

作　　者：林献武 黄明辉 LIN Xianwu;HUANG Minghui(School of Aerospace Engineering,Xiamen University,Xiamen 361102,China)

机构地区：[1]厦门大学航空航天学院,福建厦门361102

出　　处：《厦门大学学报（自然科学版）》2024年第4期583-594,共12页Journal of Xiamen University：Natural Science

基　　金：国家自然科学基金(61733017);国家自然科学基金(62273285)。

摘　　要：[目的]为了更方便地计算附加质量和提高无环流理论的严谨性,基于涡动力学理论重新推导了一种基于物面滑移速度分布计算附加质量的方法.[方法]首先基于涡动力学理论给出以流场涡量和速度表征的流体动力和力矩表达式,然后指出其收敛于无环流的条件:1)用滑移速度代替物面速度;2)力矩参考点要与刚体固连;3)令流场中的涡量强度为零.利用刚体运动可用平动参考点速度和旋转角速度来表征的特性,进一步建立平动和旋转速度与流体动力和力矩的关系,并导出附加质量新算法.基于这种新算法,分析了物体尺寸、平动参考点位置以及参考坐标系对附加质量的影响及转换方法.[结果]针对经典外形,本文方法与数值算法得到的附加质量完全一致.[结论]本文提出的新算法在附加质量计算和转换方面具有正确性和简便性.在数值计算过程中,对于采用面元法计算滑移边界速度的讨论,指出了目前面涡法在实际应用中失败的根本原因,并提出解决方案,为面元法的实际应用提供了新的思路.[Objective]In incompressible flows,the added mass is regarded as an important concept used to represent the hydrodynamics.Unfortunately,the present theory for computing this quantity cannot be readily understood and does not seem compatible with the modern vorticity dynamics.The purpose of this study lies in proposing a more comprehensible theory for computing the added mass so that these two shortcomings can be remedied.Finally,the effect of the dimension,the reference frame,and the reference point of the hydrodynamic moment on added masses are also revealed analytically to further simplify the computation.[Methods]Based on the Newton mechanics,the pressure removal method is used to develop new hydrodynamic formulae.By distinguishing the slip-boundary velocity and the solid-surface velocity,the hydrodynamic formula in non-circulatory flow is recovered.New velocity-vector-based-added-mass formulae are developed from this formula and the panel method is used to compute the velocity.Then,coordinate transformation technology is used to translate added mass between different frames.Finally,the kinematic relation of the velocity on the solid is used to clarify the effect of the dimension and the translational reference point on the added mass.[Results]New hydrodynamic formulae applicable in both non-circulatory flows and viscous flows are proposed.Compared with the classical non-circulatory flow theory,some errors are avoided under the adoption of the pressure removal method.Specifically,the pressure integration on a large far field surface is concluded to be zero in the classical theory and this conclusion conflicts with modern vorticity dynamics.Compared with the modern vorticity dynamics,the new hydrodynamic moment formula considers the effect of the reference-point velocity.This consideration not only generalizes the new formula but also explains why the present hydrodynamic moment formula in vorticity dynamics cannot be reduced to that in the classical non-circulatory flow theory.A new velocity-vector-based-added

关 键 词：流体动力 涡动力学 不可压缩流场 附加质量 面元法 

分 类 号：U661.1[交通运输工程—船舶及航道工程]