海洋構造物の流体力に及ぼす流れと波の相乗効果

概要

論文の詳細を見る
Marine structures like cylindrical bridge piers are exposed to hydrodynamic force F (=F_M + F_D, where, F_M is mass force and F_D is drag force) exerted by wave and current. While wave generates F_M and part of F_D, current generates residual part of F_D. F is calculated by Morison's formula. Ocean current velocity u is broken down into steady flow velocity ν and fluctuating wave velocity ν_w cosωt (where, ν_w is half amplitude horizontal velocity of wave, angular velocity ω = 2π/T, T is wave period and t is time). Drag force F_D (= F^^-_D + F^^〜_D, where, F^^-_D is steady drag force and F^^〜_D is fluctuating drag force) has been calculated by Fourier transform. Conclusions are as follows: (1) Steady drag force F^^-_D acting on a structure, which is primarily generated by steady velocity ν, increases under the existence of fluctuating velocity ν_w cosωt. (2) Fluctuating drag force F^^〜_D acting on a structure which is primarily generated by ν_w, increases in the same frequency components as that of wave under the existence of steady velocity ν.
2013-11-15