protected override double CalculateAerodynamicDragForce(AircraftState state)
{
double liftCoefficient = AerodynamicsHelper.CalculateLiftCoefficient(AerodynamicsData,
CalculateAngleOfAttack(state));
return(AerodynamicsHelper.CalculateDragWithEngineFailure(AerodynamicsData,
liftCoefficient,
Density,
state.TrueAirspeed));
}
public void CalculateLiftCoefficient_AerodynamicsDataNull_ThrowsArgumentNullException()
{
// Setup
var random = new Random(21);
// Call
TestDelegate call = () => AerodynamicsHelper.CalculateLiftCoefficient(null, random.NextAngle());
// Assert
var exception = Assert.Throws <ArgumentNullException>(call);
Assert.AreEqual("aerodynamicsData", exception.ParamName);
}
public static void CalculateLiftCoefficient_WithAerodynamicsData_ReturnsExpectedLiftCoefficient(AerodynamicsData aerodynamicsData)
{
// Setup
var random = new Random(21);
Angle angleOfAttack = random.NextAngle();
// Call
double liftCoefficient = AerodynamicsHelper.CalculateLiftCoefficient(aerodynamicsData,
angleOfAttack);
// Assert
double expectedLiftCoefficient = CalculateExpectedLiftCoefficient(aerodynamicsData, angleOfAttack);
Assert.AreEqual(expectedLiftCoefficient, liftCoefficient, tolerance);
}
public static void CalculateLiftCoefficient_WithInvalidAngleOfAttack_ThrowsInvalidCalculationException(AerodynamicsData aerodynamicsData,
Angle invalidAngleOfAttack,
string expectedExceptionMessage)
{
// Setup
var random = new Random(21);
// Call
TestDelegate call = () => AerodynamicsHelper.CalculateLiftCoefficient(aerodynamicsData,
invalidAngleOfAttack);
// Assert
var exception = Assert.Throws <InvalidCalculationException>(call);
Assert.AreEqual(expectedExceptionMessage, exception.Message);
}
public static void Calculate_WithAircraftStateHeightSmallerThanThresholdAndLiftSmallerThanTakeOffWeight_ReturnsExpectedTrueAirspeedRate(AircraftData aircraftData)
{
// Setup
const int nrOfFailedEngines = 1;
const double airspeed = 10.0;
const double threshold = 0.01;
var random = new Random(21);
var aircraftState = new AircraftState(aircraftData.MaximumPitchAngle,
random.NextAngle(),
airspeed,
threshold - random.NextDouble(),
random.NextDouble());
Angle angleOfAttack = aircraftState.PitchAngle - aircraftState.FlightPathAngle;
// Precondition
double lift = AerodynamicsHelper.CalculateLift(aircraftData.AerodynamicsData,
angleOfAttack,
airDensity,
airspeed);
double takeOffWeightNewton = aircraftData.TakeOffWeight * 1000; // N
Assert.IsTrue(lift < takeOffWeightNewton);
var calculator = new ContinuedTakeOffDynamicsCalculator(aircraftData, nrOfFailedEngines, airDensity, gravitationalAcceleration);
// Call
AircraftAccelerations accelerations = calculator.Calculate(aircraftState);
// Assert
double liftCoefficient = AerodynamicsHelper.CalculateLiftCoefficient(aircraftData.AerodynamicsData, angleOfAttack);
double normalForce = takeOffWeightNewton - lift;
double dragForce = AerodynamicsHelper.CalculateDragWithEngineFailure(aircraftData.AerodynamicsData,
liftCoefficient,
airDensity,
airspeed) + normalForce * aircraftData.RollingResistanceCoefficient;
double thrustForce = (aircraftData.NrOfEngines - nrOfFailedEngines) * aircraftData.MaximumThrustPerEngine * 1000;
double horizontalWeightComponent = takeOffWeightNewton * Math.Sin(aircraftState.FlightPathAngle.Radians);
double expectedAcceleration = (gravitationalAcceleration * (thrustForce - dragForce - horizontalWeightComponent))
/ takeOffWeightNewton;
Assert.AreEqual(expectedAcceleration, accelerations.TrueAirSpeedRate, tolerance);
}