SurfaceExchange.hpp

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// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2026 Caleb Buahin
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

 
#ifndef OPENSWMM_ENGINE_TRANSPORT_SURFACE_EXCHANGE_HPP
#define OPENSWMM_ENGINE_TRANSPORT_SURFACE_EXCHANGE_HPP
 
#include "../../../data/HeatOverrideData.hpp"   // HeatElement (PE1)
 
namespace openswmm {
struct SimulationContext;
}
 
namespace openswmm::transport::heat {

inline constexpr double kBowenCoeff = 0.061;

double saturationVapourPressure(double t_c) noexcept;

double latentHeatOfVaporization(double t_c) noexcept;

double windFunction(double wind_ms, double a, double b) noexcept;

double evaporationRate(double t_water_c, double t_air_c, double humidity_pct,
                       double wind_ms, double a, double b) noexcept;

double latentFlux(double t_water_c, double t_air_c, double humidity_pct,
                  double wind_ms, double a, double b,
                  double water_density) noexcept;

double bowenRatio(double t_water_c, double t_air_c, double humidity_pct,
                  double pressure_ratio) noexcept;

double sensibleFlux(double latent_flux, double bowen_ratio) noexcept;

double airTempCelsius(const SimulationContext& ctx) noexcept;

inline constexpr double kProbeC = 1.0e-3;

double relaxT(double j0, double j1, double h, double area_m2, double vol_m3,
              double dt, double rho, double cp) noexcept;

double equilibriumT(double t0_c, double j0, double j1, double h) noexcept;

inline constexpr double kSqFtToSqM = 0.09290304;
inline constexpr double kCuFtToCuM = 0.028316846592;
inline constexpr double kMphToMs = 0.44704;

double surfaceFluxOut(const SimulationContext& ctx,
                      const HeatElement& elem, double t_w) noexcept;
 
}  // namespace openswmm::transport::heat
 
#endif  // OPENSWMM_ENGINE_TRANSPORT_SURFACE_EXCHANGE_HPP