AtmosphericPressure.cpph

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// This file is part of the ExaHyPE2 project. For conditions of distribution and
// use, please see the copyright notice at www.peano-framework.org
 
#include <cmath>
 
template <auto Pa_, auto U_, auto T_, auto P0_>
static inline auto applications::exahype2::ShallowWater::R1::
  atmosphericPressure(const auto x, [[maybe_unused]] const auto y, const auto t) {
  constexpr auto lambda = U_ * T_;
  constexpr auto xShift = -0.75 * lambda; // -3/4 * U*T
 
  const auto xShifted = x + xShift;
 
  // MATLAB: phase = (x./U) - (t-1)*60;
  const auto phase = (xShifted / U_) - t;
 
  // MATLAB: tt = round(2.*phase(i)./T);
  const auto raw = 2.0 * phase / T_;
  const auto tt  = std::round(raw);
 
  if (tt >= 0 && tt <= 1) {
    // MATLAB: P0 - Pa*exp(-5.*double(tt))*sin((2*pi/T).*phase(i));
 
    const auto damping = std::exp(-5.0 * tt);
 
    const auto omega = 2.0 * M_PI / T_;
 
    return P0_ - (Pa_ * damping * std::sin(omega * phase));
  }
  return P0_;
}