Effect of Ocean Spray on Vertical Momentum Transport Under High-Wind Conditions

Abstract

Two mathematical models are proposed detailing the influence of ocean spray on vertical momentum transport under high-wind conditions associated with a hurricane or severe storm. The first model is based on a turbulent kinetic energy (TKE) equation and accounts for the so-called lubrication effect due to the reduction of turbulence intensity. The second model is based on Monin-Obukhov similarity (MOS) and uses available experimental data. It is demonstrated that the flow acceleration is negligible for wind speeds below a certain critical value due to the fact that the spray volume concentration is low for such speeds. For wind speeds higher than the critical value, the spray concentration rapidly increases, which results in significant flow acceleration. Both models produce qualitatively similar results for all turbulent flow parameters considered. It was found that the MOS-based model tends to predict a noticeably stronger lubrication effect than the TKE-based model, especially for lower wind speeds. The results of model calculations are in very good agreement with available experimental data for the spray production values near the upper bound. It is also shown that neither the value of the turbulent Schmidt number in the TKE-based model nor the choice of a stability profile function affects the spray-laden flow dynamics significantly.

The impact of waves and sea spray on modelling storm track and development

“…Recently, Rastigejev and Suslov (2014) introduced the turbulence mixing length caused by sea spray stratification into a higher order turbulence closure scheme. The reduction of the drag coefficient due to sea spray is more than in the low-order, TKE-based model (Rastigejev et al, 2011).…”

“…From the perspective of sea-spray-laden flow dynamics, the turbulent energy decreases because it requires energy to lift the sea spray droplets (Rastigejev et al, 2011). In other words, lifting the sea spray droplets reduces the atmospheric mixing, in turn reducing the airÁsea drag coefficient.…”

“…In other words, lifting the sea spray droplets reduces the atmospheric mixing, in turn reducing the airÁsea drag coefficient. Rastigejev et al (2011) proposed two numerical models to simulate the lubrication effect of sea spray based on the TKE equation and MoninÁObukhov similarity theory (MOST), respectively. Rastigejev et al (2011) found that both models can reproduce the decreasing drag coefficient when sea spray is intense and that sea spray can accelerate the airflow in the lower part of the boundary layer.…”

“…Rastigejev et al (2011) proposed two numerical models to simulate the lubrication effect of sea spray based on the TKE equation and MoninÁObukhov similarity theory (MOST), respectively. Rastigejev et al (2011) found that both models can reproduce the decreasing drag coefficient when sea spray is intense and that sea spray can accelerate the airflow in the lower part of the boundary layer. Recently, Rastigejev and Suslov (2014) introduced the turbulence mixing length caused by sea spray stratification into a higher order turbulence closure scheme.…”

Numerical Study on the Generation and Transport of Spume Droplets in Wind over Breaking Waves

“…Kudryavtsev and Makin [29] parameterized the effect of spume droplets on the turbulence mixing through stratification and found that the wind is accelerated and turbulence is suppressed due to the presence of sea spray droplets. Rastigejev et al [30] pointed out that the concentration of spray increases rapidly with the wind speed at extreme winds, which results in a significant flow acceleration, compared to the wind without sea spray droplets. Rastigejev and Suslov [31] further found that the sea spray droplets suppress the turbulent momentum flux in the airflow.…”