Surface Wave-Aerodynamic Roughness Length Model for Air-Sea Interactions

Fuente: arXiv
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Main Authors: Ayala, Manuel, Gayme, Dennice, Meneveau, Charles
Format: Preprint
Published: 2024
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author Ayala, Manuel
Gayme, Dennice
Meneveau, Charles
author_facet Ayala, Manuel
Gayme, Dennice
Meneveau, Charles
contents A new model to evaluate the equivalent hydrodynamic length or surface roughness, z0, of ocean waves is developed and tested. The proposed Surface Wave-Aerodynamic Roughness Length (SWARL) model requires maps of the wave surface height at consecutive times and the air flow characteristic Reynolds number as inputs. Pressure drag is accounted for by approximating the relative velocity in a frame moving with the local wave phase-speed assuming ideal inviscid ramp flow (Ayala et al. 2024). Drag from viscous and unresolved ripples is modeled using the standard equilibrium model. The SWARL model is tested using over 300 datasets for monochromatic and broad-spectrum wave surfaces. The model-predicted z0 and drag coefficients are compared to measured values, as well as commonly used wave parametrization methods found in the literature. For datasets with well-characterized surfaces, the proposed model shows significantly better agreement with data compared to prior models. For data that did not include a full characterization of the wave fields (typically field data), the model yields predictions with accuracy similar to prior models. Results highlight that including detailed flow physics and extensive wave-field characterization in the modeling of z0 can provide significant improvements in roughness-length based modeling of air-sea interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2412_13491
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Surface Wave-Aerodynamic Roughness Length Model for Air-Sea Interactions
Ayala, Manuel
Gayme, Dennice
Meneveau, Charles
Fluid Dynamics
Atmospheric and Oceanic Physics
Geophysics
A new model to evaluate the equivalent hydrodynamic length or surface roughness, z0, of ocean waves is developed and tested. The proposed Surface Wave-Aerodynamic Roughness Length (SWARL) model requires maps of the wave surface height at consecutive times and the air flow characteristic Reynolds number as inputs. Pressure drag is accounted for by approximating the relative velocity in a frame moving with the local wave phase-speed assuming ideal inviscid ramp flow (Ayala et al. 2024). Drag from viscous and unresolved ripples is modeled using the standard equilibrium model. The SWARL model is tested using over 300 datasets for monochromatic and broad-spectrum wave surfaces. The model-predicted z0 and drag coefficients are compared to measured values, as well as commonly used wave parametrization methods found in the literature. For datasets with well-characterized surfaces, the proposed model shows significantly better agreement with data compared to prior models. For data that did not include a full characterization of the wave fields (typically field data), the model yields predictions with accuracy similar to prior models. Results highlight that including detailed flow physics and extensive wave-field characterization in the modeling of z0 can provide significant improvements in roughness-length based modeling of air-sea interactions.
title Surface Wave-Aerodynamic Roughness Length Model for Air-Sea Interactions
topic Fluid Dynamics
Atmospheric and Oceanic Physics
Geophysics
url https://arxiv.org/abs/2412.13491