High-fidelity numerical simulation to understand the physics of surface/internal gravity wave interactions
Abstract
High-fidelity numerical simulation to understand the physics of surface/internal gravity wave interactions.The modification of ocean surface waves and the associated sea-surface roughness by internal solitary waves (ISWs) produces banded patterns on the surface that are ubiquitous in ocean satellite imagery. Convergence of surface currents leads to an increase in surface waveamplitudes and roughness, while a divergence leads to a decrease in the amplitude and roughness. While existing theories relate the surface currents to the surface waves and the satellite imagery, they are based on many simplifications including equilibrium surface wavesand simplified stratification and ISW profiles, making it difficult to quantitatively relate observed surface wave patterns to the underlying ISW currents. The objective of the proposed work is to understand the detailed physics of the interaction of surface waves and ISWs usinghigh-fidelity, multiscale numerical simulations. A large-eddy simulation (LES) code will simulate all of the scales of motion involved in the interaction, including the turbulence, surface waves, ISWs, and Langmuir cells. A potential flow solver will simulate the two-way interactionbetween surface waves with an ISW propagating in a simplified two-layer stratification. Using the fully nonlinear, three-dimensional ISW velocity field derived from the solution of the Dubriel-Jacotin-Long (DJL) equation, the potential flow solver will be used to study the one-wayinteraction between realistic ISWs and surface waves. Results from the two-layer potential flow solver will be compared to the LES model to understand the two-layer limitations. Finally, the nonlinear and nonhydrostatic SUNTANS model will be used to compute the interaction of two ISWs, and the resulting velocity fields will be used to study their impact on the surface waves using the potential flow solver. The results will provide insight into the details of the surface roughness field observed by satellite imagery which can be used to infer the properties of the ISWs, with the ultimate goal of using satellite imagery to infer the stratification for assimilationinto ocean models.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 31, 2020
- Source ID
- N000142012707
Entities
People
- Oliver Fringer
Organizations
- Office of Naval Research
- Stanford University
- United States Navy