Update SIM_balloon with Wind. #1213

trick_sims/SIM_balloon/README.md

@@ -49,6 +49,7 @@ Returns atmospheric temperature (℃) at the given altitude (m).
 
 Returns atmospheric pressure (pascals) at the given altitude (m).
 
+
 ## Dynamics Model
 
 The forces acting on our balloon will be those of gravity, buoyancy and aerodynamic drag.
@@ -151,20 +152,34 @@ Here, we can do that same calculation for air mass as before, using
 
 ---
 
-### Force of Drag
+### Force of Drag Due to Motion and Wind
+
+As a balloon moves through the air, it encounters an atmospheric drag force. This force is a function of:
+
+* the density of the surrounding air (𝝆),
+* the balloons velocity with respect to the surrounding air (v<sub>TAS</sub>),
+* the balloons coefficient of drag (C<sub>d</sub>) perpendicular to v<sub>TAS</sub>, and
+* the cross-sectional area (A) perpendicular to v<sub>TAS</sub>,
 
-As the balloon moves upward, or downward, it will be subjected to an atmospheric drag force. Drag is a function of the balloon’s shape [ represented by the coefficient of drag (C<sub>d</sub>) ], the density of the air (𝝆), and the cross-sectional area (A) perpendicular to the velocity (v). The drag force points in the opposite direction as the velocity.
 
 <a id=Equation-10></a>
 ![Equation 10](Images/Equation10.png)
 
-For our balloon, we’ll assume C<sub>d</sub> = 0.5, the coefficient of drag for a sphere.
 Since the balloon will be moving through our “standard atmosphere” 𝝆 = ```US_STD_density(altitude)```.
 
-We’ll calculate the cross-sectional area (A) from the radius of the spherical portion of our balloon.
+The velocity of the balloon through the surrounding air (v<sub>TAS</sub>) is equal to its velocity with respect to the ground (v<sub>balloon</sub>) minus the wind velocity (v<sub>wind</sub>). **TAS** stands for True air speed.
 
 <a id=Equation-11></a>
-![Equation 11](Images/Equation11.png)
+![Equation 10](Images/Equation11.png)
+
+The default value of C<sub>d</sub> = 0.5 (the coefficient of drag for a sphere) for both the horizontal and vertical axes of motion.
+
+We can calculate the cross-sectional area (A) from the radius of the spherical portion of our balloon.
+
+For vertical motion:
+![Equation 12](Images/Equation12.png)
+For horizontal motion:
+![Equation 13](Images/Equation13.png)
 
 ## Graphics
 

trick_sims/SIM_balloon/RUN_test/input.py

@@ -5,6 +5,7 @@ dyn.balloon.pos[0] = 0
 dyn.balloon.vel[0] = 0.0
 dyn.balloon.vel[1] = 0.0
 dyn.balloon.envelope_air_temperature = 92.0
+dyn.balloon.wind_speed = 0.0
 
 # ==========================================
 # Start the Satellite Graphics Client

trick_sims/SIM_balloon/models/balloon/include/Balloon.hh

@@ -18,7 +18,8 @@ class Balloon {
 	double envelope_air_temperature;
 	double envelope_radius;
 	double envelope_theta;
-	double Cd;
+	double wind_speed;
+	double Cd[2];
 
     // Calculated Variables
 	double acc[2];
@@ -27,6 +28,7 @@ class Balloon {
 
     // Control Variable
     int temperature_change_command;
+    int wind_change_command;
 
     // Methods
     int default_data();
@@ -42,7 +44,7 @@ class Balloon {
     double calc_heated_air_density();
     double calc_buoyancy_force();
     double calc_displaced_air_mass();
-    double calc_drag_force();
+    void calc_drag_force(double * F);
     double volume_of_a_spherical_dome( double r, double h);
     double volume_of_a_cone( double r, double h);
 };

trick_sims/SIM_balloon/models/balloon/src/Balloon.cpp

@@ -27,7 +27,8 @@ int Balloon::default_data() {
     envelope_radius          = 8.5;
     envelope_theta           = 45 * (M_PI/180.0);
 
-    Cd = 0.5;
+    Cd[0] = 0.5;
+    Cd[1] = 0.5;
 
     return (0);
 }
@@ -42,9 +43,13 @@ int Balloon::state_deriv() {
     double total_mass = calc_total_mass();
     double F_gravity  = total_mass * (-US_STD_gravity( pos[1])); /* Equation #2 */
     double F_buoyancy = calc_buoyancy_force();
-    double F_drag     = calc_drag_force();
+    double F_drag[2];
+    calc_drag_force(F_drag);
     acc[0] = 0.0;
-    acc[1] = (F_gravity + F_buoyancy + F_drag) / total_mass; /* Equation #1 */
+
+    acc[0] = (F_drag[0]) / total_mass;                          /* Equation #1 */
+    acc[1] = (F_gravity + F_buoyancy + F_drag[1]) / total_mass; /* Equation #1 */
+
     return(0);
 }
 
@@ -105,15 +110,29 @@ double Balloon::calc_fixed_mass() {
     return (envelope_mass + basket_mass + burner_system_mass + payload_mass);
 }
 
-double Balloon::calc_drag_force() {
+void Balloon::calc_drag_force(double *F_drag) {
+    double altitude = pos[1];
 
-    double A = M_PI * envelope_radius * envelope_radius; /* Equation 11 */
-    return (- Cd * 0.5 * US_STD_density(pos[1]) * abs(vel[1]) * vel[1] * A); /* Equation 10 */
+    /* Equation 11 */
+    double v_tas[2];
+    v_tas[0] = vel[0] - wind_speed;
+    v_tas[1] = vel[1];
+
+    double A[2];
+    A[0] = (0.75 * M_PI + 1.0) * envelope_radius * envelope_radius; /* Equation 13 */
+    A[1] = M_PI * envelope_radius * envelope_radius; /* Equation 12 */
+
+    /* Equation 10 */
+    F_drag[0] = -( 0.5 * US_STD_density(altitude) * abs(v_tas[0]) * v_tas[0] * Cd[0] * A[0] );
+    F_drag[1] = -( 0.5 * US_STD_density(altitude) * abs(v_tas[1]) * v_tas[1] * Cd[1] * A[1] );
+
+    return;
 }
 
 int Balloon::control() {
     if ( temperature_change_command != 0) {
         envelope_air_temperature += temperature_change_command;
+        temperature_change_command = 0;
     }
     if (envelope_air_temperature > 120.0) {
         envelope_air_temperature = 120.0;
@@ -121,6 +140,16 @@ int Balloon::control() {
     if (envelope_air_temperature < 80.0) {
         envelope_air_temperature = 80.0;
     }
+    if ( wind_change_command != 0) {
+        wind_speed += wind_change_command;
+        wind_change_command = 0;
+    }
+    if (wind_speed > 10.0) {
+        wind_speed = 10.0;
+    }
+    if (wind_speed < -10.0) {
+        wind_speed = -10.0;
+    }
     return(0);
 }
 

trick_sims/SIM_balloon/models/graphics/src/BalloonDisplay.java

@@ -67,6 +67,7 @@ class RangeView extends JPanel {
     private double[] balloonPos;
     private double[] balloonVel;
     private int      envelopeAirTemp; /* degrees C */
+    private int      windSpeed;
     private double   envelope_radius;
     private double   envelope_theta;
 
@@ -78,6 +79,7 @@ class RangeView extends JPanel {
 
     // Controls
     private int deltaTemp ;
+    private int deltaWind ;
 
     /**
      * Class constructor.
@@ -87,6 +89,7 @@ class RangeView extends JPanel {
         setScale(mapScale);
 
         deltaTemp = 0;
+        deltaWind = 0;
 
         skyColor    = new Color(184,202,231);
         groundColor = new Color(100,140, 60);
@@ -105,6 +108,7 @@ class RangeView extends JPanel {
         envelope_theta = Math.toRadians(45.0);
 
         envelopeAirTemp = 0;
+        windSpeed = 0;
 
         cone = new ScenePoly();
         cone.color = envelope_color_1;
@@ -152,6 +156,11 @@ class RangeView extends JPanel {
     public void resetDeltaTemp() { deltaTemp =    0; }
     public int  getDeltaTemp()   { return deltaTemp; }
 
+    public void incWind() { deltaWind =    1; }
+    public void decWind() { deltaWind =   -1; }
+    public void resetDeltaWind() { deltaWind =    0; }
+    public int  getDeltaWind()   { return deltaWind; }
+
     public void setballoonPos(double x, double y) {
         balloonPos[0] = x;
         balloonPos[1] = y;
@@ -163,6 +172,9 @@ class RangeView extends JPanel {
     public void setAirTemp(int temperature) {
         envelopeAirTemp = temperature;
     }
+    public void setWindSpeed(int speed) {
+        windSpeed = speed;
+    }
 
     public void setScale (int mapScale) {
         if (mapScale < 2) {
@@ -300,10 +312,12 @@ class RangeView extends JPanel {
         // ===============================================================================
         // Draw Information
         // ===============================================================================
+        g2d.setPaint(Color.BLACK);
         g2d.drawString ( String.format("SCALE: %d pixels/meter",scale), 20,20);
         g2d.drawString ( String.format("Envelope Air-Temp (°C) : [%d]", envelopeAirTemp), 20,40);
-        g2d.drawString ( String.format("Balloon Pos: [%.2f, %.2f]", balloonPos[0], balloonPos[1]), 20,60);
-        g2d.drawString ( String.format("Balloon Vel: [%.2f, %.2f]", balloonVel[0], balloonVel[1]), 20,80);
+        g2d.drawString ( String.format("Wind Speed (m/s) : [%d]", windSpeed), 20,60);
+        g2d.drawString ( String.format("Balloon Pos: [%.2f, %.2f]", balloonPos[0], balloonPos[1]), 20,80);
+        g2d.drawString ( String.format("Balloon Vel: [%.2f, %.2f]", balloonVel[0], balloonVel[1]), 20,100);
 
     }
 
@@ -360,12 +374,55 @@ class TemperatureCtrlPanel extends JPanel implements ActionListener {
     }
 }
 
+class WindCtrlPanel extends JPanel implements ActionListener {
+    private RangeView rangeView;
+    private JButton increaseWindButton, decreaseWindButton;
+
+    public WindCtrlPanel(RangeView view) {
+        rangeView = view;
+        setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
+        setBorder( BorderFactory.createEtchedBorder(EtchedBorder.RAISED));
+
+        increaseWindButton = new JButton("\u25b6");
+        increaseWindButton.addActionListener(this);
+        increaseWindButton.setActionCommand("increaseWind");
+        increaseWindButton.setToolTipText("Increase Wind");
+
+        decreaseWindButton = new JButton("\u25c0");
+        decreaseWindButton.addActionListener(this);
+        decreaseWindButton.setActionCommand("decreaseWind");
+        decreaseWindButton.setToolTipText("Decrease Wind");
+
+        add(decreaseWindButton);
+        add(increaseWindButton);
+
+
+    }
+
+    public void actionPerformed(ActionEvent e) {
+        String s = e.getActionCommand();
+        switch (s) {
+            case "increaseWind":
+                rangeView.incWind();
+                break;
+            case "decreaseWind":
+                rangeView.decWind();
+                break;
+            default:
+                System.out.println("Unknown Action Command:" + s);
+                break;
+        }
+    }
+}
+
+
 class ControlPanel extends JPanel implements ActionListener {
 
     private RangeView rangeView;
     private JButton zoomOutButton, zoomInButton;
     private JButton shutDownButton;
     private TemperatureCtrlPanel temperatureCtrlPanel;
+    private WindCtrlPanel windCtrlPanel;
 
     public ControlPanel(RangeView view) {
 
@@ -381,6 +438,15 @@ class ControlPanel extends JPanel implements ActionListener {
         labeledTemperatureCtrlPanel.add( temperatureCtrlPanel );
         add(labeledTemperatureCtrlPanel);
 
+        JPanel labeledWindCtrlPanel = new JPanel();
+        labeledWindCtrlPanel.setLayout(new BoxLayout(labeledWindCtrlPanel, BoxLayout.Y_AXIS));
+        JLabel windControlLabel = new JLabel("Wind Control");
+        windControlLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
+        labeledWindCtrlPanel.add(windControlLabel);
+        windCtrlPanel = new WindCtrlPanel(rangeView);
+        labeledWindCtrlPanel.add( windCtrlPanel );
+        add(labeledWindCtrlPanel);
+
         zoomOutButton = new JButton("Zoom Out");
         zoomOutButton.addActionListener(this);
         zoomOutButton.setActionCommand("zoomout");
@@ -499,9 +565,11 @@ public class BalloonDisplay extends JFrame {
         double  velx = 0.0;
         double  vely = 0.0;
         int     airtemp = 0;
+        int     windspeed = 0;
 
         // Outbound command variables
         int temperature_change_command;
+        int wind_change_command;
 
         int simMode = 0;
         boolean standalone = false;
@@ -552,6 +620,7 @@ public class BalloonDisplay extends JFrame {
                             "trick.var_add(\"dyn.balloon.vel[0]\")\n" +
                             "trick.var_add(\"dyn.balloon.vel[1]\")\n" +
                             "trick.var_add(\"dyn.balloon.envelope_air_temperature\")\n" +
+                            "trick.var_add(\"dyn.balloon.wind_speed\")\n" +
                             "trick.var_add(\"trick_sys.sched.mode\")\n" +
         //  2) We want the responses in ASCII:
                             "trick.var_ascii() \n" +
@@ -574,7 +643,8 @@ public class BalloonDisplay extends JFrame {
                 velx    = Double.parseDouble( field[3]);
                 vely    = Double.parseDouble( field[4]);
                 airtemp = Integer.parseInt( field[5]);
-                simMode = Integer.parseInt( field[6]);
+                windspeed = Integer.parseInt( field[6]);
+                simMode = Integer.parseInt( field[7]);
             } catch (IOException | NullPointerException e ) {
                 go = false;
             }
@@ -583,10 +653,19 @@ public class BalloonDisplay extends JFrame {
             rangeView.setballoonPos(posx, posy);
             rangeView.setBalloonVel(velx, vely);
             rangeView.setAirTemp(airtemp);
+            rangeView.setWindSpeed(windspeed);
 
             temperature_change_command = rangeView.getDeltaTemp();
-            balloonDisplay.out.writeBytes( String.format("dyn.balloon.temperature_change_command = %d ;\n", temperature_change_command ));
-            rangeView.resetDeltaTemp();
+            if (temperature_change_command != 0) {
+                balloonDisplay.out.writeBytes( String.format("dyn.balloon.temperature_change_command = %d ;\n", temperature_change_command ));
+                rangeView.resetDeltaTemp();
+            }
+
+            wind_change_command = rangeView.getDeltaWind();
+            if (wind_change_command != 0) {
+                balloonDisplay.out.writeBytes( String.format("dyn.balloon.wind_change_command = %d ;\n", wind_change_command ));
+                rangeView.resetDeltaWind();
+            }
 
             balloonDisplay.out.flush();