Port FluidSim core and scenarios to C++20

include/FluidSim/Crankcase.hpp

@@ -0,0 +1,37 @@
+#pragma once
+
+#include "FluidSim/Component.hpp"
+#include "FluidSim/Engine.hpp"
+#include <vector>
+
+namespace fluidsim::port {
+
+class Crankcase final : public Component {
+public:
+    Crankcase(Crankshaft& crankshaft, float crank_radius, float connecting_rod_length,
+              float bore, float clearance_volume, float initial_pressure = 101325.0f,
+              float initial_temperature = 300.0f);
+
+    Port intake_port{}, transfer_port{};
+    float pressure() const { return pressure_; }
+    float temperature() const { return temperature_; }
+    float density() const { return mass_ / (volume_ > 1e-12f ? volume_ : 1e-12f); }
+    float volume() const { return volume_; }
+    float mass() const { return mass_; }
+    float air_fraction() const { return air_fraction_; }
+
+    std::vector<Port*> ports() override { return {&intake_port, &transfer_port}; }
+    void pre_step(float dt);
+    void update_state(float dt) override;
+
+private:
+    Crankshaft& crankshaft_;
+    float crank_radius_{}, connecting_rod_length_{}, piston_area_{};
+    float clearance_volume_{}, obliquity_{};
+    float mass_{}, energy_{}, air_fraction_{1.0f};
+    float pressure_{101325.0f}, temperature_{300.0f}, volume_{}, previous_volume_{};
+
+    void sync_ports();
+};
+
+} // namespace fluidsim::port