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| //MIT License | ||
| //Copyright(c) 2020 Ivan Pensionerov | ||
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| //Permission is hereby granted, free of charge, to any person obtaining a copy | ||
| //of this software and associated documentation files (the "Software"), to deal | ||
| //in the Software without restriction, including without limitation the rights | ||
| //to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | ||
| //copies of the Software, and to permit persons to whom the Software is | ||
| //furnished to do so, subject to the following conditions: | ||
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| //The above copyright notice and this permission notice shall be included in all | ||
| //copies or substantial portions of the Software. | ||
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| //THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
| //IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
| //FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
| //AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
| //LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | ||
| //OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | ||
| //SOFTWARE. | ||
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| using System; | ||
| using UnityEngine; | ||
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| namespace SlateShipyard.Modules.Aerodynamics | ||
| { | ||
| //https://www.youtube.com/watch?v=p3jDJ9FtTyM&t=225s | ||
| //And https://ieeexplore.ieee.org/document/7152411 | ||
| //And https://github.com/gasgiant/Aircraft-Physics/blob/master/Assets/Aircraft%20Physics/Core/Scripts/AeroSurface.cs | ||
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| public class GenericWing : MonoBehaviour | ||
| { | ||
| public float SkinFriction; | ||
| public float WingArea; | ||
| public float AspectRatio; | ||
| public float LiftSlope; | ||
| public float ZeroLiftAngle; | ||
| public float StallAngleHigh; | ||
| public float StallAngleLow; | ||
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| private float FlapAngle; | ||
| public float AirfoilChord; | ||
| public float AirfoilSpan; | ||
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| public float FlapFraction; | ||
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| private OWRigidbody Body; | ||
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| public FluidDetector FluidDetector; | ||
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| public void Awake() | ||
| { | ||
| FluidDetector = GetComponent<FluidDetector>(); | ||
| } | ||
| public void Start() | ||
| { | ||
| Body = transform.GetAttachedOWRigidbody(); | ||
| } | ||
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| public void FixedUpdate() | ||
| { | ||
| Vector3 relativePos = transform.position - Body.transform.position; | ||
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| CalculateForces(FluidDetector.GetRelativeFluidVelocity(), FluidDetector.GetFluidDensity(), relativePos, out var liftForce, out Vector3 torqueForce); | ||
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| Body.AddForce(liftForce); | ||
| Body.AddTorque(torqueForce); | ||
| } | ||
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| public void SetFlapAngle(float angle) | ||
| { | ||
| FlapAngle = Mathf.Clamp(angle, -Mathf.Deg2Rad * 50, Mathf.Deg2Rad * 50); | ||
| } | ||
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| public void CalculateForces(Vector3 worldAirVelocity, float airDensity, Vector3 relativePosition, out Vector3 liftForce, out Vector3 torqueForce) | ||
| { | ||
| // Accounting for aspect ratio effect on lift coefficient. | ||
| float correctedLiftSlope = LiftSlope * AspectRatio / | ||
| (AspectRatio + 2 * (AspectRatio + 4) / (AspectRatio + 2)); | ||
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| // Calculating flap deflection influence on zero lift angle of attack | ||
| // and angles at which stall happens. | ||
| float theta = Mathf.Acos(2 * FlapFraction - 1); | ||
| float flapEffectivness = 1 - (theta - Mathf.Sin(theta)) / Mathf.PI; | ||
| float deltaLift = correctedLiftSlope * flapEffectivness * FlapEffectivnessCorrection(FlapAngle) * FlapAngle; | ||
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| float zeroLiftAoaBase = ZeroLiftAngle * Mathf.Deg2Rad; | ||
| float zeroLiftAoA = zeroLiftAoaBase - deltaLift / correctedLiftSlope; | ||
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| float stallAngleHighBase = StallAngleHigh * Mathf.Deg2Rad; | ||
| float stallAngleLowBase = StallAngleLow * Mathf.Deg2Rad; | ||
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| float clMaxHigh = correctedLiftSlope * (stallAngleHighBase - zeroLiftAoaBase) + deltaLift * LiftCoefficientMaxFraction(FlapFraction); | ||
| float clMaxLow = correctedLiftSlope * (stallAngleLowBase - zeroLiftAoaBase) + deltaLift * LiftCoefficientMaxFraction(FlapFraction); | ||
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| float stallAngleHigh = zeroLiftAoA + clMaxHigh / correctedLiftSlope; | ||
| float stallAngleLow = zeroLiftAoA + clMaxLow / correctedLiftSlope; | ||
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| // Calculating air velocity relative to the surface's coordinate system. | ||
| // Z component of the velocity is discarded. | ||
| Vector3 airVelocity = transform.InverseTransformDirection(worldAirVelocity); | ||
| airVelocity = new Vector3(0f, airVelocity.y, airVelocity.z); | ||
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| Vector3 dragDirection = transform.TransformDirection(airVelocity.normalized); | ||
| Vector3 liftDirection = Vector3.Cross(dragDirection, transform.right); | ||
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| float area = AirfoilChord * AirfoilSpan; | ||
| float dynamicPressure = 0.5f * airDensity * airVelocity.sqrMagnitude; | ||
| float angleOfAttack = Mathf.Atan2(airVelocity.y, -airVelocity.z); | ||
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| Vector3 aerodynamicCoefficients = CalculateCoefficients(angleOfAttack, | ||
| correctedLiftSlope, | ||
| zeroLiftAoA, | ||
| stallAngleHigh, | ||
| stallAngleLow); | ||
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| Vector3 lift = liftDirection * aerodynamicCoefficients.x * dynamicPressure * area; | ||
| Vector3 drag = dragDirection * aerodynamicCoefficients.y * dynamicPressure * area; | ||
| Vector3 torque = -transform.right * aerodynamicCoefficients.z * dynamicPressure * area * AirfoilChord; | ||
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| liftForce = lift + drag; | ||
| torqueForce = Vector3.Cross(relativePosition, liftForce); | ||
| torqueForce += torque; | ||
| } | ||
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| private Vector3 CalculateCoefficients(float angleOfAttack, | ||
| float correctedLiftSlope, | ||
| float zeroLiftAoA, | ||
| float stallAngleHigh, | ||
| float stallAngleLow) | ||
| { | ||
| Vector3 aerodynamicCoefficients; | ||
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| // Low angles of attack mode and stall mode curves are stitched together by a line segment. | ||
| float paddingAngleHigh = Mathf.Deg2Rad * Mathf.Lerp(15, 5, (Mathf.Rad2Deg * FlapAngle + 50) / 100); | ||
| float paddingAngleLow = Mathf.Deg2Rad * Mathf.Lerp(15, 5, (-Mathf.Rad2Deg * FlapAngle + 50) / 100); | ||
| float paddedStallAngleHigh = stallAngleHigh + paddingAngleHigh; | ||
| float paddedStallAngleLow = stallAngleLow - paddingAngleLow; | ||
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| if (angleOfAttack < stallAngleHigh && angleOfAttack > stallAngleLow) | ||
| { | ||
| // Low angle of attack mode. | ||
| aerodynamicCoefficients = CalculateCoefficientsAtLowAoA(angleOfAttack, correctedLiftSlope, zeroLiftAoA); | ||
| } | ||
| else | ||
| { | ||
| if (angleOfAttack > paddedStallAngleHigh || angleOfAttack < paddedStallAngleLow) | ||
| { | ||
| // Stall mode. | ||
| aerodynamicCoefficients = CalculateCoefficientsAtStall( | ||
| angleOfAttack, correctedLiftSlope, zeroLiftAoA, stallAngleHigh, stallAngleLow); | ||
| } | ||
| else | ||
| { | ||
| // Linear stitching in-between stall and low angles of attack modes. | ||
| Vector3 aerodynamicCoefficientsLow; | ||
| Vector3 aerodynamicCoefficientsStall; | ||
| float lerpParam; | ||
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| if (angleOfAttack > stallAngleHigh) | ||
| { | ||
| aerodynamicCoefficientsLow = CalculateCoefficientsAtLowAoA(stallAngleHigh, correctedLiftSlope, zeroLiftAoA); | ||
| aerodynamicCoefficientsStall = CalculateCoefficientsAtStall( | ||
| paddedStallAngleHigh, correctedLiftSlope, zeroLiftAoA, stallAngleHigh, stallAngleLow); | ||
| lerpParam = (angleOfAttack - stallAngleHigh) / (paddedStallAngleHigh - stallAngleHigh); | ||
| } | ||
| else | ||
| { | ||
| aerodynamicCoefficientsLow = CalculateCoefficientsAtLowAoA(stallAngleLow, correctedLiftSlope, zeroLiftAoA); | ||
| aerodynamicCoefficientsStall = CalculateCoefficientsAtStall( | ||
| paddedStallAngleLow, correctedLiftSlope, zeroLiftAoA, stallAngleHigh, stallAngleLow); | ||
| lerpParam = (angleOfAttack - stallAngleLow) / (paddedStallAngleLow - stallAngleLow); | ||
| } | ||
| aerodynamicCoefficients = Vector3.Lerp(aerodynamicCoefficientsLow, aerodynamicCoefficientsStall, lerpParam); | ||
| } | ||
| } | ||
| return aerodynamicCoefficients; | ||
| } | ||
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| private Vector3 CalculateCoefficientsAtLowAoA(float angleOfAttack, | ||
| float correctedLiftSlope, | ||
| float zeroLiftAoA) | ||
| { | ||
| float liftCoefficient = correctedLiftSlope * (angleOfAttack - zeroLiftAoA); | ||
| float inducedAngle = liftCoefficient / (Mathf.PI * AspectRatio); | ||
| float effectiveAngle = angleOfAttack - zeroLiftAoA - inducedAngle; | ||
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| float tangentialCoefficient = SkinFriction * Mathf.Cos(effectiveAngle); | ||
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| float normalCoefficient = (liftCoefficient + | ||
| Mathf.Sin(effectiveAngle) * tangentialCoefficient) / Mathf.Cos(effectiveAngle); | ||
| float dragCoefficient = normalCoefficient * Mathf.Sin(effectiveAngle) + tangentialCoefficient * Mathf.Cos(effectiveAngle); | ||
| float torqueCoefficient = -normalCoefficient * TorqCoefficientProportion(effectiveAngle); | ||
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| return new Vector3(liftCoefficient, dragCoefficient, torqueCoefficient); | ||
| } | ||
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| private Vector3 CalculateCoefficientsAtStall(float angleOfAttack, | ||
| float correctedLiftSlope, | ||
| float zeroLiftAoA, | ||
| float stallAngleHigh, | ||
| float stallAngleLow) | ||
| { | ||
| float liftCoefficientLowAoA; | ||
| if (angleOfAttack > stallAngleHigh) | ||
| { | ||
| liftCoefficientLowAoA = correctedLiftSlope * (stallAngleHigh - zeroLiftAoA); | ||
| } | ||
| else | ||
| { | ||
| liftCoefficientLowAoA = correctedLiftSlope * (stallAngleLow - zeroLiftAoA); | ||
| } | ||
| float inducedAngle = liftCoefficientLowAoA / (Mathf.PI * AspectRatio); | ||
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| float lerpParam; | ||
| if (angleOfAttack > stallAngleHigh) | ||
| { | ||
| lerpParam = (Mathf.PI / 2 - Mathf.Clamp(angleOfAttack, -Mathf.PI / 2, Mathf.PI / 2)) | ||
| / (Mathf.PI / 2 - stallAngleHigh); | ||
| } | ||
| else | ||
| { | ||
| lerpParam = (-Mathf.PI / 2 - Mathf.Clamp(angleOfAttack, -Mathf.PI / 2, Mathf.PI / 2)) | ||
| / (-Mathf.PI / 2 - stallAngleLow); | ||
| } | ||
| inducedAngle = Mathf.Lerp(0, inducedAngle, lerpParam); | ||
| float effectiveAngle = angleOfAttack - zeroLiftAoA - inducedAngle; | ||
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| float normalCoefficient = FrictionAt90Degrees(FlapAngle) * Mathf.Sin(effectiveAngle) * | ||
| (1 / (0.56f + 0.44f * Mathf.Abs(Mathf.Sin(effectiveAngle))) - | ||
| 0.41f * (1 - Mathf.Exp(-17 / AspectRatio))); | ||
| float tangentialCoefficient = 0.5f * SkinFriction * Mathf.Cos(effectiveAngle); | ||
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| float liftCoefficient = normalCoefficient * Mathf.Cos(effectiveAngle) - tangentialCoefficient * Mathf.Sin(effectiveAngle); | ||
| float dragCoefficient = normalCoefficient * Mathf.Sin(effectiveAngle) + tangentialCoefficient * Mathf.Cos(effectiveAngle); | ||
| float torqueCoefficient = -normalCoefficient * TorqCoefficientProportion(effectiveAngle); | ||
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| return new Vector3(liftCoefficient, dragCoefficient, torqueCoefficient); | ||
| } | ||
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| private float TorqCoefficientProportion(float effectiveAngle) | ||
| { | ||
| return 0.25f - 0.175f * (1 - 2 * Mathf.Abs(effectiveAngle) / Mathf.PI); | ||
| } | ||
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| private float FrictionAt90Degrees(float flapAngle) | ||
| { | ||
| return 1.98f - 4.26e-2f * flapAngle * flapAngle + 2.1e-1f * flapAngle; | ||
| } | ||
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| private float FlapEffectivnessCorrection(float flapAngle) | ||
| { | ||
| return Mathf.Lerp(0.8f, 0.4f, (Mathf.Abs(flapAngle) * Mathf.Rad2Deg - 10) / 50); | ||
| } | ||
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| private float LiftCoefficientMaxFraction(float flapFraction) | ||
| { | ||
| return Mathf.Clamp01(1 - 0.5f * (flapFraction - 0.1f) / 0.3f); | ||
| } | ||
| } | ||
| } |
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unity/SlateShipyard/Library/StateCache/SceneView/f05771-mainStage.json
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1 +1 @@ | ||
| {"cameraMode":{"drawMode":0,"name":"Shaded","section":"Shading Mode"},"sceneLighting":true,"audioPlay":false,"sceneViewState":{"showFog":true,"showMaterialUpdate":false,"showSkybox":true,"showFlares":true,"showImageEffects":true,"showParticleSystems":true},"in2DMode":false,"pivot":{"x":4.228218078613281,"y":2.043139934539795,"z":-8.39324951171875},"rotation":{"x":-0.15175656974315644,"y":-0.02758234180510044,"z":0.004208595957607031,"w":-0.9880632758140564},"size":0.7273539900779724,"orthographic":false} | ||
| {"cameraMode":{"drawMode":0,"name":"Shaded","section":"Shading Mode"},"sceneLighting":true,"audioPlay":false,"sceneViewState":{"showFog":true,"showMaterialUpdate":false,"showSkybox":true,"showFlares":true,"showImageEffects":true,"showParticleSystems":true},"in2DMode":false,"pivot":{"x":4.330411911010742,"y":3.0394883155822756,"z":-1.829643726348877},"rotation":{"x":-0.1204049363732338,"y":0.33737772703170779,"z":-0.043585143983364108,"w":-0.9326610565185547},"size":0.7273539900779724,"orthographic":false} |