A theoretical model of a wake of a body towed in a stratified fluid at large Reynolds and Froude numbers

• Published in: Nonlinear processes in geophysics Vol. 13; no. 3; pp. 247 - 253
• Main Authors: Troitskaya, Y. I., Druzhinin, O. A., Sergeev, D. A., Papko, V. V., Balandina, G. N.
• Format: Journal Article
• Language: English
• Published: Gottingen Copernicus GmbH 01-01-2006; European Geosciences Union (EGU); Copernicus Publications
• Subjects: Astrophysics; Cosmology and Extra-Galactic Astrophysics; Earth Sciences; Mathematical models; Physics; Reynolds number; Sciences of the Universe; Theoretical mathematics
• ISSN: 1607-7946; 1023-5809; 1607-7946
• DOI: 10.5194/npg-13-247-2006

The objective of the present paper is to develop a theoretical model describing the evolution of a turbulent wake behind a towed sphere in a stably stratified fluid at large Froude and Reynolds numbers. The wake flow is considered as a quasi two-dimensional (2-D) turbulent jet flow whose dynamics is governed by the momentum transfer from the mean flow to a quasi-2-D sinuous mode growing due to hydrodynamic instability. The model employs a quasi-linear approximation to describe this momentum transfer. The model scaling coefficients are defined with the use of available experimental data, and the performance of the model is verified by comparison with the results of a direct numerical simulation of a 2-D turbulent jet flow. The model prediction for the temporal development of the wake axis mean velocity is found to be in good agreement with the experimental data obtained by Spedding (1997).