Publication Date:
2022-05-26
Description:
Author Posting. © AIP Publishing, 2019. This article is posted here by permission of [publisher] for personal use, not for redistribution. The definitive version was published in Lou, Y., He, Z., Jiang, H., & Han, X. Numerical simulation of two coalescing turbulent forced plumes in linearly stratified fluids. Physics of Fluids, 31(3), (2019):037111, doi:10.1063/1.5087534.
Description:
A computational fluid dynamic model that can solve the Reynolds-averaged Navier-Stokes equations and the species transport equation is developed to simulate two coalescing turbulent forced plumes, which are released with initial momentum and buoyancy flux into a linearly stable stratified environment. The velocity fields, turbulence structures, and entrainment of two plumes with different source separations and source buoyancy fluxes are analyzed quantitatively, in comparison with a series of physical experiments. An empirical parameterization is proposed to predict the amplification of the maximum rise height of two coalescing forced plumes caused by superposition and mutual entrainment. The maximum values of both turbulent kinetic energy and turbulence dissipation rate decrease monotonically with the increase in source separation of the two turbulent plumes. However, the trajectory of the maximum turbulent viscosity attained in the plume cap region presents two notable enhancements. This variation may be attributed to the turbulence transported from the touching region and the strong mixing around the neutrally buoyant layer between two plumes, while the mixing is caused by the lateral convection and the rebound after overshooting. The plume entrainment coefficient in near vent stems has a positive relationship with the source Richardson number. A transition of flow regimes to plume-like flows would occur when the contribution of initial momentum is important. The entrainment coefficient will decrease in the touching region of two plumes due to mutual entrainment, while the superposition of plumes can lead to distortion of the boundary of plume sectors.
Description:
This work was financially supported by the National Natural Science Foundation of China (Grant No. 11672267) and Fundamental Research Funds for the Central Universities (Grant No. 2017XZZX001-02A). This work was supported by HPC Center of ZJU (Zhoushan campus). Yingzhong Lou would like to thank Liang Zhao at Zhejiang University for fruitful discussions. The authors gratefully acknowledge the constructive suggestions offered by the anonymous referees.
Description:
2020-03-28
Repository Name:
Woods Hole Open Access Server
Type:
Article
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