updates
This commit is contained in:
thzero
commit
71ffb36342
@ -1,184 +1,18 @@
|
||||
package net.sf.openrocket.simulation;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
import net.sf.openrocket.models.atmosphere.AtmosphericConditions;
|
||||
import net.sf.openrocket.rocketcomponent.InstanceMap;
|
||||
import net.sf.openrocket.rocketcomponent.RecoveryDevice;
|
||||
import net.sf.openrocket.simulation.exception.SimulationException;
|
||||
import net.sf.openrocket.util.Coordinate;
|
||||
import net.sf.openrocket.util.GeodeticComputationStrategy;
|
||||
import net.sf.openrocket.util.MathUtil;
|
||||
import net.sf.openrocket.util.WorldCoordinate;
|
||||
|
||||
public abstract class AbstractEulerStepper extends AbstractSimulationStepper {
|
||||
private static final Logger log = LoggerFactory.getLogger(AbstractEulerStepper.class);
|
||||
|
||||
private static final double RECOVERY_TIME_STEP = 0.5;
|
||||
|
||||
protected double cd;
|
||||
public class BasicLandingStepper extends AbstractEulerStepper {
|
||||
|
||||
@Override
|
||||
public SimulationStatus initialize(SimulationStatus status) {
|
||||
this.cd = computeCD(status);
|
||||
return status;
|
||||
protected double computeCD(SimulationStatus status) {
|
||||
// Accumulate CD for all recovery devices
|
||||
cd = 0;
|
||||
final InstanceMap imap = status.getConfiguration().getActiveInstances();
|
||||
for (RecoveryDevice c : status.getDeployedRecoveryDevices()) {
|
||||
cd += imap.count(c) * c.getCD() * c.getArea() / status.getConfiguration().getReferenceArea();
|
||||
}
|
||||
|
||||
private double getCD() {
|
||||
return cd;
|
||||
}
|
||||
|
||||
protected abstract double computeCD(SimulationStatus status);
|
||||
|
||||
@Override
|
||||
public void step(SimulationStatus status, double maxTimeStep) throws SimulationException {
|
||||
|
||||
// Get the atmospheric conditions
|
||||
AtmosphericConditions atmosphere = modelAtmosphericConditions(status);
|
||||
|
||||
//// Local wind speed and direction
|
||||
Coordinate windSpeed = modelWindVelocity(status);
|
||||
Coordinate airSpeed = status.getRocketVelocity().add(windSpeed);
|
||||
|
||||
// Compute drag force
|
||||
double mach = airSpeed.length() / atmosphere.getMachSpeed();
|
||||
double dynP = (0.5 * atmosphere.getDensity() * airSpeed.length2());
|
||||
double dragForce = getCD() * dynP * status.getConfiguration().getReferenceArea();
|
||||
|
||||
// n.b. this is constant, and could be calculated once at the beginning of this simulation branch...
|
||||
double rocketMass = calculateStructureMass(status).getMass();
|
||||
double motorMass = calculateMotorMass(status).getMass();
|
||||
|
||||
double mass = rocketMass + motorMass;
|
||||
|
||||
// Compute drag acceleration
|
||||
Coordinate linearAcceleration;
|
||||
if (airSpeed.length() > 0.001) {
|
||||
linearAcceleration = airSpeed.normalize().multiply(-dragForce / mass);
|
||||
} else {
|
||||
linearAcceleration = Coordinate.NUL;
|
||||
}
|
||||
|
||||
// Add effect of gravity
|
||||
double gravity = modelGravity(status);
|
||||
linearAcceleration = linearAcceleration.sub(0, 0, gravity);
|
||||
|
||||
|
||||
// Add coriolis acceleration
|
||||
Coordinate coriolisAcceleration = status.getSimulationConditions().getGeodeticComputation().getCoriolisAcceleration(
|
||||
status.getRocketWorldPosition(), status.getRocketVelocity());
|
||||
linearAcceleration = linearAcceleration.add(coriolisAcceleration);
|
||||
|
||||
// Select tentative time step
|
||||
double timeStep = RECOVERY_TIME_STEP;
|
||||
|
||||
// adjust based on change in acceleration (ie jerk)
|
||||
final double jerk = Math.abs(linearAcceleration.sub(status.getRocketAcceleration()).multiply(1.0/status.getPreviousTimeStep()).length());
|
||||
if (jerk > MathUtil.EPSILON) {
|
||||
timeStep = Math.min(timeStep, 1.0/jerk);
|
||||
}
|
||||
|
||||
// but don't let it get *too* small
|
||||
timeStep = Math.max(timeStep, MIN_TIME_STEP);
|
||||
log.trace("timeStep is " + timeStep);
|
||||
|
||||
// Perform Euler integration
|
||||
Coordinate newPosition = status.getRocketPosition().add(status.getRocketVelocity().multiply(timeStep)).
|
||||
add(linearAcceleration.multiply(MathUtil.pow2(timeStep) / 2));
|
||||
|
||||
// If I've hit the ground, recalculate time step and position
|
||||
if (newPosition.z < 0) {
|
||||
|
||||
final double a = linearAcceleration.z;
|
||||
final double v = status.getRocketVelocity().z;
|
||||
final double z0 = status.getRocketPosition().z;
|
||||
|
||||
// The new timestep is the solution of
|
||||
// 1/2 at^2 + vt + z0 = 0
|
||||
timeStep = (-v - Math.sqrt(v*v - 2*a*z0))/a;
|
||||
log.trace("ground hit changes timeStep to " + timeStep);
|
||||
|
||||
newPosition = status.getRocketPosition().add(status.getRocketVelocity().multiply(timeStep)).
|
||||
add(linearAcceleration.multiply(MathUtil.pow2(timeStep) / 2));
|
||||
|
||||
// avoid rounding error in new altitude
|
||||
newPosition = newPosition.setZ(0);
|
||||
}
|
||||
|
||||
status.setSimulationTime(status.getSimulationTime() + timeStep);
|
||||
status.setPreviousTimeStep(timeStep);
|
||||
|
||||
status.setRocketPosition(newPosition);
|
||||
status.setRocketVelocity(status.getRocketVelocity().add(linearAcceleration.multiply(timeStep)));
|
||||
status.setRocketAcceleration(linearAcceleration);
|
||||
|
||||
// Update the world coordinate
|
||||
WorldCoordinate w = status.getSimulationConditions().getLaunchSite();
|
||||
w = status.getSimulationConditions().getGeodeticComputation().addCoordinate(w, status.getRocketPosition());
|
||||
status.setRocketWorldPosition(w);
|
||||
|
||||
// Store data
|
||||
FlightDataBranch data = status.getFlightData();
|
||||
boolean extra = status.getSimulationConditions().isCalculateExtras();
|
||||
data.addPoint();
|
||||
|
||||
data.setValue(FlightDataType.TYPE_TIME, status.getSimulationTime());
|
||||
data.setValue(FlightDataType.TYPE_ALTITUDE, status.getRocketPosition().z);
|
||||
data.setValue(FlightDataType.TYPE_POSITION_X, status.getRocketPosition().x);
|
||||
data.setValue(FlightDataType.TYPE_POSITION_Y, status.getRocketPosition().y);
|
||||
|
||||
airSpeed = status.getRocketVelocity().add(windSpeed);
|
||||
if (extra) {
|
||||
data.setValue(FlightDataType.TYPE_POSITION_XY,
|
||||
MathUtil.hypot(status.getRocketPosition().x, status.getRocketPosition().y));
|
||||
data.setValue(FlightDataType.TYPE_POSITION_DIRECTION,
|
||||
Math.atan2(status.getRocketPosition().y, status.getRocketPosition().x));
|
||||
|
||||
data.setValue(FlightDataType.TYPE_VELOCITY_XY,
|
||||
MathUtil.hypot(status.getRocketVelocity().x, status.getRocketVelocity().y));
|
||||
data.setValue(FlightDataType.TYPE_ACCELERATION_XY,
|
||||
MathUtil.hypot(linearAcceleration.x, linearAcceleration.y));
|
||||
|
||||
data.setValue(FlightDataType.TYPE_ACCELERATION_TOTAL, linearAcceleration.length());
|
||||
|
||||
double Re = airSpeed.length() *
|
||||
status.getConfiguration().getLengthAerodynamic() /
|
||||
atmosphere.getKinematicViscosity();
|
||||
data.setValue(FlightDataType.TYPE_REYNOLDS_NUMBER, Re);
|
||||
}
|
||||
|
||||
|
||||
data.setValue(FlightDataType.TYPE_LATITUDE, status.getRocketWorldPosition().getLatitudeRad());
|
||||
data.setValue(FlightDataType.TYPE_LONGITUDE, status.getRocketWorldPosition().getLongitudeRad());
|
||||
data.setValue(FlightDataType.TYPE_GRAVITY, gravity);
|
||||
|
||||
if (status.getSimulationConditions().getGeodeticComputation() != GeodeticComputationStrategy.FLAT) {
|
||||
data.setValue(FlightDataType.TYPE_CORIOLIS_ACCELERATION, coriolisAcceleration.length());
|
||||
}
|
||||
|
||||
|
||||
data.setValue(FlightDataType.TYPE_VELOCITY_Z, status.getRocketVelocity().z);
|
||||
data.setValue(FlightDataType.TYPE_ACCELERATION_Z, linearAcceleration.z);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_VELOCITY_TOTAL, airSpeed.length());
|
||||
data.setValue(FlightDataType.TYPE_MACH_NUMBER, mach);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_MASS, mass);
|
||||
data.setValue(FlightDataType.TYPE_MOTOR_MASS, motorMass);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_THRUST_FORCE, 0);
|
||||
data.setValue(FlightDataType.TYPE_DRAG_FORCE, dragForce);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_WIND_VELOCITY, windSpeed.length());
|
||||
data.setValue(FlightDataType.TYPE_AIR_TEMPERATURE, atmosphere.getTemperature());
|
||||
data.setValue(FlightDataType.TYPE_AIR_PRESSURE, atmosphere.getPressure());
|
||||
data.setValue(FlightDataType.TYPE_SPEED_OF_SOUND, atmosphere.getMachSpeed());
|
||||
|
||||
data.setValue(FlightDataType.TYPE_TIME_STEP, timeStep);
|
||||
data.setValue(FlightDataType.TYPE_COMPUTATION_TIME,
|
||||
(System.nanoTime() - status.getSimulationStartWallTime()) / 1000000000.0);
|
||||
log.trace("time " + data.getLast(FlightDataType.TYPE_TIME) + ", altitude " + data.getLast(FlightDataType.TYPE_ALTITUDE) + ", velocity " + data.getLast(FlightDataType.TYPE_VELOCITY_Z));
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
184
core/src/net/sf/openrocket/simulation/AbstractEulerStepper.java
Normal file
184
core/src/net/sf/openrocket/simulation/AbstractEulerStepper.java
Normal file
@ -0,0 +1,184 @@
|
||||
package net.sf.openrocket.simulation;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
import net.sf.openrocket.models.atmosphere.AtmosphericConditions;
|
||||
import net.sf.openrocket.rocketcomponent.InstanceMap;
|
||||
import net.sf.openrocket.rocketcomponent.RecoveryDevice;
|
||||
import net.sf.openrocket.simulation.exception.SimulationException;
|
||||
import net.sf.openrocket.util.Coordinate;
|
||||
import net.sf.openrocket.util.GeodeticComputationStrategy;
|
||||
import net.sf.openrocket.util.MathUtil;
|
||||
import net.sf.openrocket.util.WorldCoordinate;
|
||||
|
||||
public abstract class AbstractEulerStepper extends AbstractSimulationStepper {
|
||||
private static final Logger log = LoggerFactory.getLogger(AbstractEulerStepper.class);
|
||||
|
||||
private static final double RECOVERY_TIME_STEP = 0.5;
|
||||
|
||||
protected double cd;
|
||||
|
||||
@Override
|
||||
public SimulationStatus initialize(SimulationStatus status) {
|
||||
this.cd = computeCD(status);
|
||||
return status;
|
||||
}
|
||||
|
||||
private double getCD() {
|
||||
return cd;
|
||||
}
|
||||
|
||||
protected abstract double computeCD(SimulationStatus status);
|
||||
|
||||
@Override
|
||||
public void step(SimulationStatus status, double maxTimeStep) throws SimulationException {
|
||||
|
||||
// Get the atmospheric conditions
|
||||
AtmosphericConditions atmosphere = modelAtmosphericConditions(status);
|
||||
|
||||
//// Local wind speed and direction
|
||||
Coordinate windSpeed = modelWindVelocity(status);
|
||||
Coordinate airSpeed = status.getRocketVelocity().add(windSpeed);
|
||||
|
||||
// Compute drag force
|
||||
double mach = airSpeed.length() / atmosphere.getMachSpeed();
|
||||
double dynP = (0.5 * atmosphere.getDensity() * airSpeed.length2());
|
||||
double dragForce = getCD() * dynP * status.getConfiguration().getReferenceArea();
|
||||
|
||||
// n.b. this is constant, and could be calculated once at the beginning of this simulation branch...
|
||||
double rocketMass = calculateStructureMass(status).getMass();
|
||||
double motorMass = calculateMotorMass(status).getMass();
|
||||
|
||||
double mass = rocketMass + motorMass;
|
||||
|
||||
// Compute drag acceleration
|
||||
Coordinate linearAcceleration;
|
||||
if (airSpeed.length() > 0.001) {
|
||||
linearAcceleration = airSpeed.normalize().multiply(-dragForce / mass);
|
||||
} else {
|
||||
linearAcceleration = Coordinate.NUL;
|
||||
}
|
||||
|
||||
// Add effect of gravity
|
||||
double gravity = modelGravity(status);
|
||||
linearAcceleration = linearAcceleration.sub(0, 0, gravity);
|
||||
|
||||
|
||||
// Add coriolis acceleration
|
||||
Coordinate coriolisAcceleration = status.getSimulationConditions().getGeodeticComputation().getCoriolisAcceleration(
|
||||
status.getRocketWorldPosition(), status.getRocketVelocity());
|
||||
linearAcceleration = linearAcceleration.add(coriolisAcceleration);
|
||||
|
||||
// Select tentative time step
|
||||
double timeStep = RECOVERY_TIME_STEP;
|
||||
|
||||
// adjust based on change in acceleration (ie jerk)
|
||||
final double jerk = Math.abs(linearAcceleration.sub(status.getRocketAcceleration()).multiply(1.0/status.getPreviousTimeStep()).length());
|
||||
if (jerk > MathUtil.EPSILON) {
|
||||
timeStep = Math.min(timeStep, 1.0/jerk);
|
||||
}
|
||||
|
||||
// but don't let it get *too* small
|
||||
timeStep = Math.max(timeStep, MIN_TIME_STEP);
|
||||
log.trace("timeStep is " + timeStep);
|
||||
|
||||
// Perform Euler integration
|
||||
Coordinate newPosition = status.getRocketPosition().add(status.getRocketVelocity().multiply(timeStep)).
|
||||
add(linearAcceleration.multiply(MathUtil.pow2(timeStep) / 2));
|
||||
|
||||
// If I've hit the ground, recalculate time step and position
|
||||
if (newPosition.z < 0) {
|
||||
|
||||
final double a = linearAcceleration.z;
|
||||
final double v = status.getRocketVelocity().z;
|
||||
final double z0 = status.getRocketPosition().z;
|
||||
|
||||
// The new timestep is the solution of
|
||||
// 1/2 at^2 + vt + z0 = 0
|
||||
timeStep = (-v - Math.sqrt(v*v - 2*a*z0))/a;
|
||||
log.trace("ground hit changes timeStep to " + timeStep);
|
||||
|
||||
newPosition = status.getRocketPosition().add(status.getRocketVelocity().multiply(timeStep)).
|
||||
add(linearAcceleration.multiply(MathUtil.pow2(timeStep) / 2));
|
||||
|
||||
// avoid rounding error in new altitude
|
||||
newPosition = newPosition.setZ(0);
|
||||
}
|
||||
|
||||
status.setSimulationTime(status.getSimulationTime() + timeStep);
|
||||
status.setPreviousTimeStep(timeStep);
|
||||
|
||||
status.setRocketPosition(newPosition);
|
||||
status.setRocketVelocity(status.getRocketVelocity().add(linearAcceleration.multiply(timeStep)));
|
||||
status.setRocketAcceleration(linearAcceleration);
|
||||
|
||||
// Update the world coordinate
|
||||
WorldCoordinate w = status.getSimulationConditions().getLaunchSite();
|
||||
w = status.getSimulationConditions().getGeodeticComputation().addCoordinate(w, status.getRocketPosition());
|
||||
status.setRocketWorldPosition(w);
|
||||
|
||||
// Store data
|
||||
FlightDataBranch data = status.getFlightData();
|
||||
boolean extra = status.getSimulationConditions().isCalculateExtras();
|
||||
data.addPoint();
|
||||
|
||||
data.setValue(FlightDataType.TYPE_TIME, status.getSimulationTime());
|
||||
data.setValue(FlightDataType.TYPE_ALTITUDE, status.getRocketPosition().z);
|
||||
data.setValue(FlightDataType.TYPE_POSITION_X, status.getRocketPosition().x);
|
||||
data.setValue(FlightDataType.TYPE_POSITION_Y, status.getRocketPosition().y);
|
||||
|
||||
airSpeed = status.getRocketVelocity().add(windSpeed);
|
||||
if (extra) {
|
||||
data.setValue(FlightDataType.TYPE_POSITION_XY,
|
||||
MathUtil.hypot(status.getRocketPosition().x, status.getRocketPosition().y));
|
||||
data.setValue(FlightDataType.TYPE_POSITION_DIRECTION,
|
||||
Math.atan2(status.getRocketPosition().y, status.getRocketPosition().x));
|
||||
|
||||
data.setValue(FlightDataType.TYPE_VELOCITY_XY,
|
||||
MathUtil.hypot(status.getRocketVelocity().x, status.getRocketVelocity().y));
|
||||
data.setValue(FlightDataType.TYPE_ACCELERATION_XY,
|
||||
MathUtil.hypot(linearAcceleration.x, linearAcceleration.y));
|
||||
|
||||
data.setValue(FlightDataType.TYPE_ACCELERATION_TOTAL, linearAcceleration.length());
|
||||
|
||||
double Re = airSpeed.length() *
|
||||
status.getConfiguration().getLengthAerodynamic() /
|
||||
atmosphere.getKinematicViscosity();
|
||||
data.setValue(FlightDataType.TYPE_REYNOLDS_NUMBER, Re);
|
||||
}
|
||||
|
||||
|
||||
data.setValue(FlightDataType.TYPE_LATITUDE, status.getRocketWorldPosition().getLatitudeRad());
|
||||
data.setValue(FlightDataType.TYPE_LONGITUDE, status.getRocketWorldPosition().getLongitudeRad());
|
||||
data.setValue(FlightDataType.TYPE_GRAVITY, gravity);
|
||||
|
||||
if (status.getSimulationConditions().getGeodeticComputation() != GeodeticComputationStrategy.FLAT) {
|
||||
data.setValue(FlightDataType.TYPE_CORIOLIS_ACCELERATION, coriolisAcceleration.length());
|
||||
}
|
||||
|
||||
|
||||
data.setValue(FlightDataType.TYPE_VELOCITY_Z, status.getRocketVelocity().z);
|
||||
data.setValue(FlightDataType.TYPE_ACCELERATION_Z, linearAcceleration.z);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_VELOCITY_TOTAL, airSpeed.length());
|
||||
data.setValue(FlightDataType.TYPE_MACH_NUMBER, mach);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_MASS, mass);
|
||||
data.setValue(FlightDataType.TYPE_MOTOR_MASS, motorMass);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_THRUST_FORCE, 0);
|
||||
data.setValue(FlightDataType.TYPE_DRAG_FORCE, dragForce);
|
||||
|
||||
data.setValue(FlightDataType.TYPE_WIND_VELOCITY, windSpeed.length());
|
||||
data.setValue(FlightDataType.TYPE_AIR_TEMPERATURE, atmosphere.getTemperature());
|
||||
data.setValue(FlightDataType.TYPE_AIR_PRESSURE, atmosphere.getPressure());
|
||||
data.setValue(FlightDataType.TYPE_SPEED_OF_SOUND, atmosphere.getMachSpeed());
|
||||
|
||||
data.setValue(FlightDataType.TYPE_TIME_STEP, timeStep);
|
||||
data.setValue(FlightDataType.TYPE_COMPUTATION_TIME,
|
||||
(System.nanoTime() - status.getSimulationStartWallTime()) / 1000000000.0);
|
||||
log.trace("time " + data.getLast(FlightDataType.TYPE_TIME) + ", altitude " + data.getLast(FlightDataType.TYPE_ALTITUDE) + ", velocity " + data.getLast(FlightDataType.TYPE_VELOCITY_Z));
|
||||
}
|
||||
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user