/*
 * PS3Prob2.java
 *
 * Created on February 22, 2002, 3:24 PM
 */

/**
 *
 * @author  Curtis Eubanks
 * @version
 */
import java.util.Vector;
import javax.swing.JOptionPane;

public class PS3Prob2 {
    
    /** Creates new PS3Prob2 */
    public PS3Prob2() {
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        Fluid[] fluids = new Fluid[4];
        fluids[0] = new Fluid("water", 1.0E3, 1.0E-3);
        fluids[1] = new Fluid("air", 1.2, 1.8E-5);
        fluids[2] = new Fluid("ethyl alcohol", 0.79E3, 1.2E-3);
        fluids[3] = new Fluid("methyl alcohol", 0.79E3, 0.62E-3);
        
        String fluidInput = JOptionPane.showInputDialog("Enter fluid type (1=water, 2=air, 3=ethyl alcohol, 4=methyl alcohol");
        int fluidIndex = Integer.parseInt(fluidInput)-1;
        
        Vector pipes = new Vector(5);
        
        Pipe ab = new Pipe("AB", 0.5, 50.0, -0.1);
        pipes.addElement(ab);
        
        Pipe bc = new Pipe("BC", 0.4, 15, -0.05);
        ab.addOutflow(bc);
        pipes.addElement(bc);
        
        Pipe cd = new Pipe("CD", 0.3, 5.0, -0.03);
        bc.addOutflow(cd);
        pipes.addElement(cd);
        
        Pipe ce = new Pipe("CE", Math.sqrt(7.0)/10.0, 8.0, -0.03);
        bc.addOutflow(ce);
        pipes.addElement(ce);
        
        Pipe bf = new Pipe("BF", 0.3, 25.0, 0.05);
        ab.addOutflow(bf);
        pipes.addElement(bf);
        
        String input = JOptionPane.showInputDialog("Initial pressure at A: ");
        double initialPressure = Double.parseDouble(input);
        
        input = JOptionPane.showInputDialog("Initial velocity at A: ");
        double initialVelocity = Double.parseDouble(input);
        
        input = JOptionPane.showInputDialog("Enter pipe roughness: ");
        Pipe.setRoughness(Double.parseDouble(input));
        
        /* start the juices flowing */
        /* this will calculate input & output pressures for all pipes in the network */
        ab.startFlow(fluids[fluidIndex], initialVelocity, initialPressure);
        
        /* compute desired quantities */
        for (int i=0; i < pipes.size(); i++) {
            Pipe pipe = (Pipe)pipes.elementAt(i);
            pipe.printPipeInfo(fluids[fluidIndex], initialVelocity, initialPressure);
        }
        System.exit(0);
    }
}

class Fluid {
    private String name;
    private double density;
    private double viscosity;
    public Fluid(String name, double density, double viscosity) {
        this.name = name;
        this.density = density;
        this.viscosity = viscosity;
    }
    public String toString() {
        return "Fluid: \"" + name +"\", density = " + density + ", viscosity = " + viscosity;
    }
    
    public double getDensity() {
        return density;
    }
    
    public double getViscosity() {
        return viscosity;
    }
}

class Pipe {
    private static double roughness = 0.00001; /* in meters */
    
    /* gravitational acceleration on the earth's surface at sea level */
    final private static double g = 9.8; /* in meters/sec^2 */
    
    private String name;
    private double diameter;        /* in meters */
    private double length;          /* in meters */
    private double elevationChange; /* in meters */
    
    /* the pressure (if calculated) */
    public double inPressure, outPressure;
    
    /* list of Pipe objects whose input is our output */
    private Vector outflows;
    
    public Pipe(String name, double diameter, double length, double elevationChange) {
        this.name = name;
        this.diameter = diameter;
        this.length = length;
        this.elevationChange = elevationChange;
        
        inPressure = 0.0; /* empty pipe */
        outPressure = 0.0; /* empty pipe */
        
        outflows = new Vector();
    }
    
    public void addOutflow(Pipe p) {
        outflows.addElement(p);
    }
    
    public void startFlow(Fluid fluid, double velocity, double inputPressure) {
        inPressure = inputPressure;
        outPressure = pressureChange(inputPressure, fluid, velocity);
        
        /* calculate pressure of all outflows */
        for (int i=0; i<outflows.size(); i++) {
            Pipe outPipe = (Pipe)outflows.elementAt(i);
            outPipe.startFlow(fluid, velocity, outPressure);
        }
    }
    
    public String toString() {
        return "Pipe: \"" + name + "\", length = " + length + ", diameter = " + diameter;
    }
    
    public double getReynoldsNumber(Fluid fluid, double velocity) {
        return fluid.getDensity() * velocity * diameter / fluid.getViscosity();
    }
    
    public double pressureChange(double initialPressure, Fluid fluid, double velocity) {
        return initialPressure - fluid.getDensity() * g * (elevationChange + getf(fluid, velocity)*length*velocity*velocity/(2*diameter*g));
    }
    
    private double getf(Fluid fluid, double v) {
        double R = getReynoldsNumber(fluid, v);
        
        return R < 2000.0 ? (64.0/R) :
            Math.pow(1.81 * log10(6.9/R + Math.pow(roughness/(3.7*diameter), 1.11)), -2.0);
    }
    
    public double flowVolume(double velocity) {
        double radius = diameter / 2.0;
        return Math.PI * radius * radius * velocity;
    }
    static public double log10(double n) {
        /* log10(x) = ln(x) * log10(e) */
        return Math.log(n)* 0.434294482;
    }
    static public double getRoughness() {
        return roughness;
    }
    
    static public void setRoughness(double rough) {
        Pipe.roughness = rough;
    }
    
    public void printPipeInfo(Fluid fluid, double velocity, double inputPressure) {
        double pc = pressureChange(inputPressure, fluid, velocity);
        System.out.println("Pipe \"" + name + "\":");
        System.out.println("  Diameter = " + diameter);
        System.out.println("  Length = " + length);
        System.out.println("  Elevation change = " + elevationChange);
        System.out.println("  Roughness = " + getRoughness());
        System.out.println("  Reynolds number = " + getReynoldsNumber(fluid, velocity));
        System.out.println("  friction = " + getf(fluid, velocity));
        System.out.println("  Input pressure = " + inPressure);
        System.out.println("  Output pressure = " + outPressure);
        System.out.println("  Output flow volume = " + flowVolume(velocity));
    }
}