ON LONG-WAVE BREAKING Ⅰ.CONSIDERING nTH POWER BOTTOM FRICTION     

田纪伟  娄顺里  胡敦欣  李鸿雁  张法高 《中国海洋湖沼学报》1995,(2)

Longwave breaking is the agent for many important upper ocean layer processes including the trans-fer of horizontal momentum. In a previous study on the process of longwave breaking, only linear bot-tom friction was considered.In this paper, we discuss the longwave breaking phenomena in the moregeneral case of nth power bottom friction. Using the theory of blowup of solution,the criterion for thetime and location of the longwave breaking can be obtained.  相似文献   

CHARACTER OF SIMPLIFIED NAVIER-STOKES EQUATIONS FOR NEAR THE LEADING EDGE PART OF TWO-DIMENSIONAL LAMINAR FLOW PAST A FLAT PLATE     

田纪伟  王新生 《中国海洋湖沼学报》1994,12(4):351-360

Starting from the Simplified Navier-Stokes(SNS)equations presented at first by Godovachev-Kuzmin-Tsopov,and Gao Zhi,Davis,the authors analyze the character of the SNS equations for the laminarflow near the leading edge of a flat plate and far away from the plate by using the Weiner—Hopf meth-od and Fourier transform.It is proved that the solution of the SNS equations agree with the solution of the Navier-Stokes equations for flow near the leading edge of the plate and far away from the plate.How to match the solution of the SNS equations to the Blasius solution of the boundary layer equationsis also discussed.  相似文献   

层结海洋中小振幅内行进波的演变和破碎   总被引：1，自引：0，他引：1       下载免费PDF全文

李丙瑞  田纪伟  范海梅  刘志亮  赵骞 《地球物理学报》2006,49(2):360-366

采用高精度的拟谱方法，数值模拟了层结海洋中小振幅内行进波的演变和破碎过程.在演变过程中，导致内波破碎的PSI不稳定机制在共振相互作用中逐渐占据主导地位，能量从初级波向低频、高波数运动缓慢传递并形成一次级波包，随即破碎发生.破碎后产生的层化湍流引起的强烈混合以及湍流间歇性可从总能量和涡度峰度随时间的变化趋势看出.我们分析了层化湍流的一些统计特性，包括动能和有效位能沿垂向波数ky的功率谱.结果表明，动能和有效位能谱都存在一个谱段满足k-3y律，且分别可表示为01N4k-3y和02N4k-3y(N为Brunt Visl频率)，通常称其为浮力子区.另外，我们分析了Cox数(湍流扩散系数与分子扩散系数之比)，在层化湍流维持在一定强度时，计算结果和由海洋内区观测(远离内波强生成源和复杂地形)所推测的结论较为吻合.  相似文献   

Turbulent dissipation and mixing in Prydz Bay     

杨庆轩  田纪伟  赵玮  谢玲玲 《中国海洋湖沼学报》2013,31(2):445-453

In this paper,we present measurements of velocity,temperature,salinity,and turbulence collected in Prydz Bay,Antarctica,during February,2005.The dissipation rates of turbulent kinetic energy(ε) and diapycnal diffusivities(K z) were estimated along a section in front of the Amery Ice Shelf.The dissipation rates and diapycnal diffusivities were spatially non-uniform,with higher values found in the western half of the section where ε reached 10-7 W/kg and K z reached 10-2 m 2 /s,about two and three orders of magnitude higher than those in the open ocean,respectively.In the western half of the section both the dissipation rates and diffusivities showed a high-low-high vertical structure.This vertical structure may have been determined by internal waves in the upper layer,where the ice shelf draft acts as a possible energy source,and by bottom-generated internal waves in the lower layer,where both tides and geostrophic currents are possible energy sources.The intense diapycnal mixing revealed in our observations could contribute to the production of Antarctic Bottom Water in Prydz Bay.  相似文献   

海洋白浪寿命的定义及测量结果   总被引：3，自引：0，他引：3  

楼顺里  曹露洁  田纪伟 《海洋与湖沼》1998,29(2):183-190

通过对国内外白浪研究和应用的分析,首次提出了有效白浪寿命的定义,给出了计算白浪寿命的公式及测量方法和结果,并报告了以此方法在渤海实测的结果,得到了白浪寿命ＴＬ与海面风速Ｕ１０的关系为ＴＬ＝０．２６Ｕ１０以及白浪寿命概率分布近于瑞利分布等。  相似文献   

小振幅海洋内波的演变、破碎和所致混合   总被引：1，自引：1，他引：0       下载免费PDF全文

李丙瑞  范海梅  田纪伟  孙波  张占海 《海洋与湖沼》2010,41(6):807-815

利用基于谱方法和MPI并行运算的数值模式SpectralModel,直接数值模拟了三维小振幅海洋内波的演变、破碎和所致湍流混合,指出导致其不稳定而破碎的为PSI(parametric subharmonic instability)机制;对于内波破碎所致的湍流混合过程,分析了跨等密度面扩散系数kρ、混合效率γ、浮力通量谱、动能谱以及势能谱等统计性质:内波破碎前,kρ和γ保持低值水平,浮力通量谱值为负,且集中在低波数段;内波破碎后,kρ和γ迅速增大,最大值分别约为0.9×103m2/s和0.18,浮力通量谱值在低波数段为负值,在高波数段为正值,这是因为层化湍流中势能向小尺度运动传递和动能向小尺度运动传递相比更为有效。在内波破碎、强湍流混合阶段,势能谱存在一谱段满足kz3律,P(kz)=0.2N2kz3。此外,与二维模拟结果相比较,导致内波不稳定而破碎的均为PSI机制,kρ、浮力通量谱、势能谱变化趋势大体一致;但三维数值实验中,内波破碎时间提前,湍流衰减加快;KE谱在高波数部分下降速度相对减小,更接近于kz3。  相似文献