A simple empirical formula for predicting the maximum wave–current force in wave–current coexisting fields

Kawamata, Shigeru; Manabu Kobayashi

doi:10.51094/jxiv.2315

##article.authors##

Kawamata, Shigeru Japan Fisheries Research and Education Agency, Fisheries Technology Institute, Kamisu Branch
Manabu Kobayashi International Meteorological and Oceanographic Consultants Co. Ltd

DOI:

https://doi.org/10.51094/jxiv.2315

キーワード:

Wave orbital velocity、 Maximum wave–current force、 Combined wave–current flow

抄録

This paper demonstrates that the maximum wave–current force (F_p) acting on a stationary body in combined wave–current flows with arbitrary intersection angles can be expressed by the simple formula F_p = ρ C_FA V_m²/2, where ρ is the density of fluid, C_F the maximum force coefficient, A the reference area of the body, and V_m the vector sum of the wave-induced velocity amplitude U_a and the current velocity U_c . It assumes that, as the velocity ratio U_c /(U_c + U_a ) varies from 0 to 1, C_F gradually varies from the wave-only maximum force coefficient C_F,w to the steady drag coefficient C_DS , where C_F,w is given by a function of a Keulegan–Carpenter number K_C. The validity of the formula was checked by measuring the forces acting on a complex-shaped body oscillating in steady currents at different intersection angles in a circulating water channel (CWC). The experimental and predicted F_p values were within 20% in the inertial regime. The C_F,w–K_C relationship from the CWC test showed reasonable agreement with that from an additional wave flume test with asymmetric velocity waveforms, supporting the validity of the CWC test results and the wide applicability of the formula.

利益相反に関する開示

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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