| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | March 17, 2020 |
| Latest Amendment Date: | March 17, 2020 |
| Award Number: | 1947960 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Baris Uz
bmuz@nsf.gov (703)292-4557 OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | April 1, 2020 |
| End Date: | September 30, 2023 (Estimated) |
| Total Intended Award Amount: | $99,689.00 |
| Total Awarded Amount to Date: | $99,689.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
75 LOWER COLLEGE RD RM 103 KINGSTON RI US 02881-1974 (401)874-2635 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Narragansett Bay Campus Narragansett RI US 02882-3739 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | PHYSICAL OCEANOGRAPHY |
| Primary Program Source: |
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| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Wave breaking is a crucial process affecting a variety of ocean and coastal science and engineering problems both offshore and in the nearshore of great societal importance. This study will develop algorithms for the detection of wave breaking initiation, breaking conditions, and energy dissipation due to wave breaking, for use in phase-resolving ocean wave propagations models. Extensive validation and sensitivity analysis will be performed against recent high-fidelity numerical simulations and laboratory and field data. The robustness of the developed formulations will also be compared with existing breaking models. In addition to developing the parametrizations, this study will quantify uncertainties associated with various parametrizations of wave breaking in operational phase-resolving wave models. The model-field data comparison during storm conditions will benefit the coastal engineering community by better identifying model skill and uncertainty during storms and extreme events. The work will improve predictions of the occurrence and severity of breaking waves in phase-resolving wave models leading to: (i) a more accurate representation of wave-forcing (on currents, sediment processes, air-sea interactions, etc.) over a range of water depths, including the inner shelf, the surf zone, and river mouths; (ii) improved design analyses and safety for coastal and ocean structures and ship design. A better prediction of breaking processes and impacts during energetic/storm events will also benefit the public through improved strategies for coastal resilience. A junior scientist at the University of Washington (UW), the lead PI, will be mentored by the more senior co-PIs, which will help him transition to a permanent appointment. The project will support a female graduate student at the University of Delaware, who will be co-advised by the PIs. Outreach will be conducted at the annual "Discovery Days" event at the University of Washington.
A new, unified, and robust closure model for parameterization of the onset and progression of wave breaking in phase-resolving, energy-conserving surface wave models is proposed, applicable to Boussinesq (commonly used in shallow water) and High-Order Spectral (HOS, commonly used in deep water) models. The proposed work is motivated by and builds on recent results obtained using high-fidelity numerical simulations, which establish that the onset and strength of breaking of an individual wave crest can be determined solely from local properties of the evolving crest as it approaches breaking in arbitrary depth. The new closure model will improve on existing methods by providing a formulation that is adaptive to individual wave crests, as opposed to being calibrated based on the general features of the wave train. Extensive validation and sensitivity analysis of the proposed breaking closure model will be performed against recent high-fidelity numerical simulations, available laboratory experiments, and recent and ongoing field observations during storm conditions. Both the latter data and its use in numerical modeling are quite novel and will establish a unique model-field data comparison procedure as it requires initialization of the phase-resolving model using a wave field reconstruction algorithm. The robustness of the proposed breaking closure model will also be compared with existing breaking models.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Wave breaking is one of the most important and complex phenomena affecting ocean waves. Impact forces from such waves are the largest ones that affect ships and both offshore and coastal structures used for energy production or coastal protection. The momentum and mass (sea sprays) that breaking waves exchange with the atmosphere significantly affects air-sea interactions and the development and evolution of storms. And the energy and momentum dissipated by breaking waves nearshore are the driving processes for instantaneous flow velocities, mean coastal currents, wave set-up, and turbulence, that all govern sediment suspension, transport, and deposition and ultimately the shaping of erodible shoreline and coastal morphology. In this work, focusing on bathymetry-induced wave breaking, we further developed, implemented in a variety of high-fidelity energy-conserving wave models, and validated, a unified model for predicting wave breaking onset and parameterizing its resulting energy dissipation. The class of model considered are those used in operational nearshore and coastal wave modeling, in science and engineering, that resolve individual waves for realistic irregular sea states, and accurately represent the bottom bathymetry, the shoreline and any submerged or emerged coastal feature or structures that would interact with storm waves. The main feature of the new parameterization is that it is nearly universal and directly determined by local wave properties; and it accurately applies equally to waves of any scale, from short wind waves to tsunamis. In applications published so far, we compared results of wave simulations using potential flow or Boussinesq wave models, in which the new breaking onset/dissipation formulation was implemented, to results of full Navier-Stokes models and of laboratory experiments, both in two- and three-dimensions. The predictive ability of the new models was found to be excellent in all cases. Note that for Boussinesq models, we ended up modifying the solution scheme in order to achieve better results, yielding much improved simulations of breaking waves in our operational fully-nonlinear Boussinesq model FUNWAVE (with publications on these aspects still in preparation). The latter model has become a standard with many agencies (e.g., The US Army Corps of Engineers) and coastal engineering companies in both the US and abroad.
In the course of this project, the junior scientist who was the principal investigator was mentored by the senior co-PIs and, eventually, secured a permanent and more senior position at his insitution. A female PhD student in engineering was trained and graduated in the US; she now works as a coastal research scientists. Two PhD students (one female) were co-advised in France, in engineering institutions, as part of a collaboration with the URI PI, and have graduated; both work in private engineering companies.
Last Modified: 01/04/2024
Modified by: Stephan T Grilli
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