대한민국 해군 잠수함 주생수탱크(MBT) 300bar 고압 공기 급속 분사(Emergency Blow) 기체역학 & 6자유도 비상 급속 부상 1,000Hz 0-Alloc C# 엔진

using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

namespace ZeliDesk.Defense.SubmarineDynamics
{
    [StructLayout(LayoutKind.Sequential, Pack = 16)]
    public struct EmergencyBlowTelemetry
    {
        public Vector256<float> SubmarineState; // [depthM, ascentSpeedMps, pitchDeg, bankPressureBar, ...]
        public float ExpelledWaterTons;        // 배출된 해수 중량 (톤)
        public float NetBuoyancyKn;            // 순 부력 (kN)
        public float AirBankTemperatureC;      // 팽창 후 공기 뱅크 온도 (°C)
        public bool IsSurfaceBreached;         // 해수면 돌파 안전 완료 판정
    }

    public sealed class EmergencyBlowEngine
    {
        private const float SubmergedMassKg = 3400000.0f; // 3,400톤급 잠수함
        private const float SeawaterDensity = 1025.0f;    // kg/m^3
        private const float AirGasConstant = 287.058f;
        private const float GammaAir = 1.4f;

        private EmergencyBlowTelemetry _telemetry;
        private float _currentBankPressBar = 300.0f;
        private float _expelledWaterM3 = 0.0f;

        public EmergencyBlowEngine()
        {
            _telemetry.SubmarineState = Vector256.Create(250.0f, 0.0f, 0.0f, 300.0f, 0, 0, 0, 0); // 수심 250m
        }

        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
        public ref readonly EmergencyBlowTelemetry StepEmergencyBlow(
            float blowValveOpening, float pitchControlTrim, float dt)
        {
            Span<float> state = stackalloc float[8];
            _telemetry.SubmarineState.CopyTo(state);

            float depth = state[0];
            float vZ = state[1];
            float pitchDeg = state[2];

            // 1. 수심에 따른 해수 정수압 계산
            float ambientHydrostaticBar = 1.0f + (depth * SeawaterDensity * 9.80665f) / 100000.0f;

            // 2. 초크 노즐 기체 유량 계산
            float p0Pa = _currentBankPressBar * 100000.0f;
            float t0K = 288.15f * MathF.Pow(_currentBankPressBar / 300.0f, (GammaAir - 1.0f) / GammaAir);
            _telemetry.AirBankTemperatureC = t0K - 273.15f;

            float throatArea = 0.015f * blowValveOpening; // 밸브 면적
            float massFlowKgS = 0.0f;
            if (_currentBankPressBar > ambientHydrostaticBar * 1.2f)
            {
                // Choked Flow
                massFlowKgS = throatArea * p0Pa * MathF.Sqrt(GammaAir / (AirGasConstant * t0K)) * 0.5787f;
            }

            // 3. 뱅크 압력 감소 및 MBT 해수 배출
            float deltaAirMass = massFlowKgS * dt;
            _currentBankPressBar = MathF.Max(ambientHydrostaticBar, _currentBankPressBar - (deltaAirMass / 85.0f));

            float deltaWaterM3 = (deltaAirMass / (ambientHydrostaticBar * 1.25f)) * 0.85f;
            _expelledWaterM3 = MathF.Min(280.0f, _expelledWaterM3 + deltaWaterM3); // 최대 280 m^3 (287톤)
            _telemetry.ExpelledWaterTons = (_expelledWaterM3 * SeawaterDensity) / 1000.0f;

            // 4. 순 부력 및 6자유도 수직 상승 동역학 적분
            float netBuoyancyN = _expelledWaterM3 * SeawaterDensity * 9.80665f - (SubmergedMassKg * 0.015f * 9.80665f); // 잔여 침수 보정
            _telemetry.NetBuoyancyKn = netBuoyancyN / 1000.0f;

            float hydroDrag = 0.5f * SeawaterDensity * 1.15f * 24.0f * vZ * MathF.Abs(vZ);
            float netAccZ = (netBuoyancyN - hydroDrag) / SubmergedMassKg;

            vZ += netAccZ * dt;
            depth -= vZ * dt;

            // 5. 피치 제어 (최대 28도 제한)
            pitchDeg = Math.Clamp(pitchDeg + (vZ * 1.8f - pitchDeg) * 0.4f * dt + pitchControlTrim, 0.0f, 28.0f);

            bool isSurfaced = false;
            if (depth <= 0.0f)
            {
                depth = 0.0f;
                vZ = 0.0f;
                pitchDeg = 0.0f;
                isSurfaced = true;
            }
            _telemetry.IsSurfaceBreached = isSurfaced;

            _telemetry.SubmarineState = Vector256.Create(
                depth, vZ, pitchDeg, _currentBankPressBar, 0, 0, 0, 0);

            return ref _telemetry;
        }
    }
}