!> author: 左志华 !> date: 2022-09-16 !> !> Seakeeping wave theory <br> !> 耐波性波浪理论 !>### 参考 !> 1. 船舶原理（上）<br> !> 2. 如何让水中涟漪变成拍岸巨浪？水面波的形成原因和增强原理. module seakeeping_wave use seakeeping_kinds, only: rk => sk_real_kind use seakeeping_constants, only: g, Pi, pi2 implicit none private public :: k01, k02, we, wlr, wf, wenergy, zeta, vdeep, & ittc_tpwes_waveamplitude, ccwes_waveamplitude, ittc_spwes_waveamplitude contains !> Wave number from wave frequency <br> !> 波频率计算波数 elemental real(rk) function k01(w) result(k0) real(rk), intent(in) :: w k0 = w*w/g end function k01 !> Wave number from wave length <br> !> 波长计算波数 elemental real(rk) function k02(l) result(k0) real(rk), intent(in) :: l k0 = pi2/l end function k02 !> Encountered wave frequency <br> !> 遭遇波频率 elemental real(rk) function we(w, v, deg) real(rk), intent(in) :: w !! Wave frequency <br> !! 波频率 real(rk), intent(in) :: v !! Ship speed <br> !! 船舶速度 real(rk), intent(in), optional :: deg !! Ship heading <br> !! 船舶航向 if (present(deg)) then we = w + k01(w)*v*cos(deg) else we = w + k01(w)*v end if end function we !> Wavelength to length ratio <br> !> 波长与船长比 elemental real(rk) function wlr(w, l) real(rk), intent(in) :: w !! Wave frequency <br> !! 波频率 real(rk), intent(in) :: l !! Ship length <br> !! 船舶特征长度 wlr = pi2/(k01(w)*l) end function wlr !> Wave frequency from wlr <br> !> 由波长与船长比计算波频率 elemental real(rk) function wf(wlr, l) real(rk), intent(in) :: wlr !! Wavelength to length ratio <br> !! 波长与船长比 real(rk), intent(in) :: l !! Ship length <br> !! 船舶特征长度 wf = sqrt(g*k02(wlr*l)) end function wf !> Wave energy <br> !> 波能：动能 + 势能, \( energy = 0.5*ρ*A^2*g \) elemental real(rk) function wenergy(rho, a) real(rk), intent(in) :: rho !! Water density <br> !! 水密度 real(rk), intent(in) :: a !! Wave amplitude <br> !! 波幅 wenergy = rho*g*a*a/2 end function wenergy !> 单位波幅：\\( \zeta = \sin(kx\cos\beta + ky\sin\beta + \omega t + phase) \\) real(rk) pure function zeta(k, x, y, w, t, beta, phase) real(rk), intent(in) :: k, x, y, w, t, beta, phase zeta = sin(k*x*cos(beta) + k*y*sin(beta) + w*t + phase) end function zeta !> 深水波波速 \( v = \sqrt{\frac{g\lambda}{2\pi}} \) !>@note 确保水深大于半波长，造波机多次前后移动制造深水波，波长越大的后波将追赶前波， !> 最终水面波可叠加形成一条大浪 real(rk) pure function vdeep(lambda) real(rk), intent(in) :: lambda vdeep = sqrt(g*lambda/(pi2)) end function vdeep !> 12th-ITTC (1969) 双参数波能谱模型计算频段有义波幅 !> ITTC two-parameter wave energy spectrum pure subroutine ittc_tpwes_waveamplitude(omega, domega, t1, hs, wave_amplitude) real(kind=rk), intent(in) :: omega !! 波浪角频率, rad/s real(kind=rk), intent(in) :: domega !! 频率间隔, rad/s real(kind=rk), intent(in) :: t1 !! 平均周期, s, T1 = 2*pi*m0/m1 real(kind=rk), intent(in) :: hs !! 有义波高, m real(kind=rk), intent(out) :: wave_amplitude !! 频段有义波幅, m real(kind=rk) :: s associate (a => 173*hs**2/t1**4, b => 691/t1**4) s = a*exp(-b/omega**4)/omega**5 wave_amplitude = sqrt(2*s*domega) ! A = sqrt(2*S_\omega*d\omega) end associate end subroutine ittc_tpwes_waveamplitude !> 11th-ITTC (1966) 单参数波能谱模型计算频段有义波幅 !> ITTC single-parameter wave energy spectrum pure subroutine ittc_spwes_waveamplitude(omega, domega, hs, wave_amplitude) real(kind=rk), intent(in) :: omega !! 波浪角频率, rad/s real(kind=rk), intent(in) :: domega !! 频率间隔, rad/s real(kind=rk), intent(in) :: hs !! 有义波高, m real(kind=rk), intent(out) :: wave_amplitude !! 频段有义波幅, m real(kind=rk) :: s real(kind=rk), parameter :: a = 8.1e-3_rk*g**2 associate (b => 3.11_rk/hs**2) s = a*exp(-b/omega**4)/omega**5 wave_amplitude = sqrt(2*s*domega) ! A = sqrt(2*S_\omega*d\omega) end associate end subroutine ittc_spwes_waveamplitude !> 中国沿海波能谱模型计算频段有义波幅 !> China Coastal Wave Energy Spectrum pure subroutine ccwes_waveamplitude(omega, domega, hs, wave_amplitude) real(kind=rk), intent(in) :: omega !! 波浪角频率, rad/s real(kind=rk), intent(in) :: domega !! 频率间隔, rad/s real(kind=rk), intent(in) :: hs !! 有义波高, m real(kind=rk), intent(out) :: wave_amplitude !! 频段有义波幅, m real(kind=rk) :: s associate (u => 6.28_rk*sqrt(hs)) s = 0.74_rk*exp(-(g/(u*omega))**2)/omega**5 wave_amplitude = sqrt(2*s*domega) ! A = sqrt(2*S_\omega*d\omega) end associate end subroutine ccwes_waveamplitude end module seakeeping_wave