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Title: Computational Modelling and Experimental Tank Testing of the Multi Float WaveSub under Regular Wave Forcing

Abstract

A submerged wave device generates energy from the relative motion of floating bodies. In WaveSub, three floats are joined to a reactor; each connected to a spring and generator. Electricity generated damps the orbital movements of the floats. The forces are non-linear and each float interacts with the others. Tuning to the wave climate is achieved by changing the line lengths, so there is a need to understand the performance trade-offs for a large number of configurations. This requires an efficient, large displacement, multidirectional, multi-body numerical scheme. Results from a 1/25 scale wave basin experiment are described. Here, we show that a time domain linear potential flow formulation (Nemoh, WEC-Sim) can match the tank testing provided that suitably tuned drag coefficients are employed. Inviscid linear potential models can match some wave device experiments; however, additional viscous terms generally provide better accuracy. Scale experiments are also prone to mechanical friction, and we estimate friction terms to improve the correlation further. The resulting error in mean power between numerical and physical models is approximately 10%. Predicted device movement shows a good match. Overall, drag terms in time domain wave energy modelling will improve simulation accuracy in wave renewable energy device design. tomore » understand the performance trade-offs for a large number of configurations. This requires an efficient, large displacement, multidirectional, multi-body numerical scheme. Results from a 1/25 scale wave basin experiment are described. Here, we show that a time domain linear potential flow formulation (Nemoh, WEC-Sim) can match the tank testing provided that suitably tuned drag coefficients are employed. Inviscid linear potential models can match some wave device experiments; however, additional viscous terms generally provide better accuracy. Scale experiments are also prone to mechanical friction, and we estimate friction terms to improve the correlation further. The resulting error in mean power between numerical and physical models is approximately 10%. Predicted device movement shows a good match. Overall, drag terms in time domain wave energy modelling will improve simulation accuracy in wave renewable energy device design.« less

Authors:
 [1];  [2];  [2];  [3];  [3];  [4];  [4]; ORCiD logo [5];  [6];  [1];  [2];  [2]
  1. Swansea University
  2. Marine Power Systems Ltd.
  3. University of Bath
  4. University of Plymouth
  5. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
  6. Sandia National Laboratories
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE-4W)
OSTI Identifier:
1600898
Report Number(s):
NREL/JA-5000-75769
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
Renewable Energy
Additional Journal Information:
Journal Volume: 152
Country of Publication:
United States
Language:
English
Subject:
16 TIDAL AND WAVE POWER; renewable energy; wave energy; tank testing; wave potential theory; damping

Citation Formats

Faraggiana, E., Whitlam, C., Chapman, J., Hillis, A., Roesner, J., Hann, M., Greaves, D., Yu, Yi-Hsiang, Ruehl, K., Masters, I., Foster, G., and Stockman, G. Computational Modelling and Experimental Tank Testing of the Multi Float WaveSub under Regular Wave Forcing. United States: N. p., 2020. Web. doi:10.1016/j.renene.2019.12.146.
Faraggiana, E., Whitlam, C., Chapman, J., Hillis, A., Roesner, J., Hann, M., Greaves, D., Yu, Yi-Hsiang, Ruehl, K., Masters, I., Foster, G., & Stockman, G. Computational Modelling and Experimental Tank Testing of the Multi Float WaveSub under Regular Wave Forcing. United States. doi:10.1016/j.renene.2019.12.146.
Faraggiana, E., Whitlam, C., Chapman, J., Hillis, A., Roesner, J., Hann, M., Greaves, D., Yu, Yi-Hsiang, Ruehl, K., Masters, I., Foster, G., and Stockman, G. Thu . "Computational Modelling and Experimental Tank Testing of the Multi Float WaveSub under Regular Wave Forcing". United States. doi:10.1016/j.renene.2019.12.146.
@article{osti_1600898,
title = {Computational Modelling and Experimental Tank Testing of the Multi Float WaveSub under Regular Wave Forcing},
author = {Faraggiana, E. and Whitlam, C. and Chapman, J. and Hillis, A. and Roesner, J. and Hann, M. and Greaves, D. and Yu, Yi-Hsiang and Ruehl, K. and Masters, I. and Foster, G. and Stockman, G.},
abstractNote = {A submerged wave device generates energy from the relative motion of floating bodies. In WaveSub, three floats are joined to a reactor; each connected to a spring and generator. Electricity generated damps the orbital movements of the floats. The forces are non-linear and each float interacts with the others. Tuning to the wave climate is achieved by changing the line lengths, so there is a need to understand the performance trade-offs for a large number of configurations. This requires an efficient, large displacement, multidirectional, multi-body numerical scheme. Results from a 1/25 scale wave basin experiment are described. Here, we show that a time domain linear potential flow formulation (Nemoh, WEC-Sim) can match the tank testing provided that suitably tuned drag coefficients are employed. Inviscid linear potential models can match some wave device experiments; however, additional viscous terms generally provide better accuracy. Scale experiments are also prone to mechanical friction, and we estimate friction terms to improve the correlation further. The resulting error in mean power between numerical and physical models is approximately 10%. Predicted device movement shows a good match. Overall, drag terms in time domain wave energy modelling will improve simulation accuracy in wave renewable energy device design. to understand the performance trade-offs for a large number of configurations. This requires an efficient, large displacement, multidirectional, multi-body numerical scheme. Results from a 1/25 scale wave basin experiment are described. Here, we show that a time domain linear potential flow formulation (Nemoh, WEC-Sim) can match the tank testing provided that suitably tuned drag coefficients are employed. Inviscid linear potential models can match some wave device experiments; however, additional viscous terms generally provide better accuracy. Scale experiments are also prone to mechanical friction, and we estimate friction terms to improve the correlation further. The resulting error in mean power between numerical and physical models is approximately 10%. Predicted device movement shows a good match. Overall, drag terms in time domain wave energy modelling will improve simulation accuracy in wave renewable energy device design.},
doi = {10.1016/j.renene.2019.12.146},
journal = {Renewable Energy},
number = ,
volume = 152,
place = {United States},
year = {2020},
month = {1}
}