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- Title
An Improved Second‐Moment Closure Model for Langmuir Turbulence Conditions: Model Derivation and Validation.
- Authors
Yu, W.; Song, J. B.; Cao, A. Z.; Yin, B. S.; Guan, S. D.
- Abstract
In this study, an improved second‐moment closure model, the so‐called k‐ω model, which takes into consideration the Langmuir turbulent effect in the transport equations of turbulent kinetic energy and turbulent frequency, was developed. The Langmuir turbulent effect was also included in the vertical eddy viscosity and diffusivity coefficient. Langmuir turbulence production, as well as buoyancy production, anisotropic production, and vorticity production induced by velocity shear, was included in the pressure covariance parameterization to derive the stability function. The Langmuir effect and relatively complete pressure covariance parameterization inclusion can account for the influences of Langmuir turbulence and stratification in the vertical eddy viscosity and vertical eddy diffusion coefficients. Based on the modified model, one‐dimensional numerical experiments for horizontally homogeneous flows were carried out. The results indicate that the modified model is more accurate than other models in terms of the vertical eddy viscosity, vertical turbulence velocity variance, kinetic energy, and mean velocity profile compared with the large eddy simulation results. The simulated sea surface temperature (SST) and mixed layer depth of the modified model were compared with observations at Ocean Station Papa. When considering Langmuir turbulent effects, the modified model overcomes the shortcoming that the simulated SST is higher than the observed SST. Numerical results indicate that the k‐ω model performs better than the k‐kl model, although both models consider the Langmuir turbulent effect in the simulation of upper mixing motions. Plain Language Summary: In this work, we obtain a modified k‐ω model which include the Langmuir turbulent effect in the turbulent kinetic energy equation and turbulent frequency transport equation. The modified mixing model by proposed new stability function for the vertical eddy viscosity and diffusivity. The Langmuir turbulence effect and a relatively complete pressure strain covariance parameterization both be taken account to derive new stability functions. And the new model can give reasonable results in the condition mentioned in this article. Key Points: A modified k‐ω model incorporating Langmuir turbulent effects in the turbulent kinetic energy equation and turbulent frequency transport equation is proposedA new stability function for vertical eddy viscosity and diffusivity is proposed in the modified mixing model. Both the Langmuir turbulent effect and relatively complete pressure strain covariance parameterization are taken into consideration to derive new stability functionsThe modified model gives reasonable results, which are more consistent with large eddy simulation and observations than those of other models
- Subjects
BUOYANCY; OCEAN temperature; PLASMA Langmuir waves; KINETIC energy; OCEAN currents; CLIMATE research
- Publication
Journal of Geophysical Research. Oceans, 2018, Vol 123, Issue 12, p9010
- ISSN
2169-9275
- Publication type
Article
- DOI
10.1029/2018JC013878