水利水电科技进展
水利水電科技進展
수이수전과기진전
ADVANCES IN SCIENCE AND TECHNOLOGY OF WATER RESOURCES
2014年
4期
82-88,94
,共8页
梁书秀%严斌%孙昭晨%张怡辉
樑書秀%嚴斌%孫昭晨%張怡輝
량서수%엄빈%손소신%장이휘
湍流封闭格式%压力项%扩散项%耗散项%波浪混合
湍流封閉格式%壓力項%擴散項%耗散項%波浪混閤
단류봉폐격식%압력항%확산항%모산항%파랑혼합
second-order turbulence closure%pressure relations%diffusions%dissipations%wave mixing
针对目前海洋环流模式预测能力存在的不足,从雷诺应力方程着手,归纳和阐述了二阶湍流闭合模式中压力项、扩散项和耗散项的改进与发展,分析和讨论了各种改进格式对模型完善和预测能力的影响,同时分析了波浪混合作用对环流封闭格式的影响,并对海洋环流模式中二阶湍流封闭格式发展进行了简要综述。压力项的改进主要集中于压力项中各影响量的添加,使得可以模拟的湍流的理查森数Ri趋近1;扩散项的改进主要通过改善湍流能量扩散的第三稳定函数Sk 来完成;对于耗散率的改进更多是基于经验,用与理查德森数相联系的阶梯型函数可以有效模拟强分层流;环流模式中通过模拟波浪对垂向扩散系数的影响和在紊动动能方程中考虑波浪破碎耗散的能量的注入,都可以从物理机制上改善目前模式所模拟的混合层太浅和温跃层强度偏低的共性问题。
針對目前海洋環流模式預測能力存在的不足,從雷諾應力方程著手,歸納和闡述瞭二階湍流閉閤模式中壓力項、擴散項和耗散項的改進與髮展,分析和討論瞭各種改進格式對模型完善和預測能力的影響,同時分析瞭波浪混閤作用對環流封閉格式的影響,併對海洋環流模式中二階湍流封閉格式髮展進行瞭簡要綜述。壓力項的改進主要集中于壓力項中各影響量的添加,使得可以模擬的湍流的理查森數Ri趨近1;擴散項的改進主要通過改善湍流能量擴散的第三穩定函數Sk 來完成;對于耗散率的改進更多是基于經驗,用與理查德森數相聯繫的階梯型函數可以有效模擬彊分層流;環流模式中通過模擬波浪對垂嚮擴散繫數的影響和在紊動動能方程中攷慮波浪破碎耗散的能量的註入,都可以從物理機製上改善目前模式所模擬的混閤層太淺和溫躍層彊度偏低的共性問題。
침대목전해양배류모식예측능력존재적불족,종뢰낙응력방정착수,귀납화천술료이계단류폐합모식중압력항、확산항화모산항적개진여발전,분석화토론료각충개진격식대모형완선화예측능력적영향,동시분석료파랑혼합작용대배류봉폐격식적영향,병대해양배류모식중이계단류봉폐격식발전진행료간요종술。압력항적개진주요집중우압력항중각영향량적첨가,사득가이모의적단류적리사삼수Ri추근1;확산항적개진주요통과개선단류능량확산적제삼은정함수Sk 래완성;대우모산솔적개진경다시기우경험,용여리사덕삼수상련계적계제형함수가이유효모의강분층류;배류모식중통과모의파랑대수향확산계수적영향화재문동동능방정중고필파랑파쇄모산적능량적주입,도가이종물리궤제상개선목전모식소모의적혼합층태천화온약층강도편저적공성문제。
A brief review of the development of second-order turbulence closure is presented aiming to overcome the two deficiencies in the prediction of the ocean circulation model. The paper begins from Reynolds stress equations, analyzes and summarizes the improvement and development of pressure relations term, diffusions term, and dissipations term aiming at stating the effects of the terms on the prediction ability of corresponding turbulence closure. Finally, the different ways to consider the wave mixing in ocean circulation model are discussed as well. The improvement of pressure correlation focuses on adding the relative terms such that the Richardson's number of the turbulence approaches 1. The diffusion term is improved by the third stability function Sk . The improvement of dissipation relies on the empiricism by using the Heaviside step function to simulate the strong stable stratified flow. In simulating the wave impact on the vertical diffusion coefficient and injecting energy dissipated in wave breaking into turbulent kinetic energy equation, the two general problems-too shallow mixing layer and the low intensity of the thermocline-may be improved physically.