FluidSim/Components/Atmosphere.cs

using FluidSim.Interfaces;

namespace FluidSim.Components
{
    /// <summary>
    /// Represents the ambient atmosphere – constant pressure/temperature reservoir.
    /// </summary>
    public class Atmosphere : IComponent
    {
        public double Pressure { get; set; } = 101325.0;
        public double Temperature { get; set; } = 300.0;
        public double GasConstant { get; set; } = 287.0;
        public double Gamma => 1.4;

        public double Density => Pressure / (GasConstant * Temperature);
        public double SpecificEnthalpy => Gamma / (Gamma - 1.0) * Pressure / Density;

        public Port Port { get; }

        public Atmosphere()
        {
            Port = new Port { Owner = this };
            UpdatePort();
        }

        public IReadOnlyList<Port> Ports => new[] { Port };

        public void UpdateState(double dt)
        {
            // Atmosphere is static – just ensure the port reflects current values
            UpdatePort();
        }

        private void UpdatePort()
        {
            Port.Pressure = Pressure;
            Port.Density = Density;
            Port.Temperature = Temperature;
            Port.SpecificEnthalpy = SpecificEnthalpy;
            // MassFlowRate is set by the solver connector
        }
    }
}