{ "metadata": { "name": "", "signature": "sha256:4641f495fb637b43843e8fcd55506866f439259b641b4627c67482beed84d471" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 4 : Conservation Principle of Momentum" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.1 Page No : 111" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "#Initialization of variables\n", "Q = 0.2 \t\t\t#m**3/s\n", "v = 30. \t\t\t#m/s\n", "angle = 120. \t\t\t#degrees\n", "rho = 1000. \t\t\t#kg/m**3\n", "\t\t\t\n", "#calculations\n", "Rx = rho*Q*(v-v*math.cos(math.radians(angle)))\n", "Ry = rho*Q*v*math.sin(math.radians(angle))\n", "R = math.sqrt(Rx**2 +Ry**2)\n", "\t\t\t\n", "#results\n", "print \"Resultant force = %.2f kN\"%(R/1000)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Resultant force = 10.39 kN\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.3 Page No : 112" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "#Initialization of variables\n", "angle = 45. \t\t#degrees\n", "p1 = 150.*10**3 \t#pressure at inlet - N/m**2\n", "Q = 0.5 \t\t\t#rate of flow - m**3/s\n", "d1 = 60. \t\t\t#cm\n", "d2 = 30. \t\t\t#cm\n", "rho = 1000. \t\t#kg/m**3\n", "g = 9.81 \t\t\t#m/s**2\n", "\t\t\t\n", "#calculations\n", "V1 = Q/(math.pi/4 *(d1/100)**2)\n", "V2 = V1*(d1/d2)**2\n", "P2 = rho*g*(p1/(rho*g) + V1**2 /(2*g) -V2**2 /(2*g))\n", "Rx = p1*math.pi/4*(d1/100)**2 - P2*math.pi/4 *(d2/100)**2 *math.cos(math.radians(angle)) -rho*Q*(V2*math.cos(math.radians(angle)) -V1)\n", "Ry = P2*math.pi/4 *(d2/100)**2 *math.sin(math.radians(angle)) + rho*Q*(V2*math.sin(math.radians(angle)))\n", "R = math.sqrt(Rx**2 + Ry**2)\n", "\t\t\t\n", "#results\n", "print \"resultant force = %.2f kN\"%(R/1000)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "resultant force = 35.58 kN\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.4 Page No : 113" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "#Initialization of variables\n", "Q = 20.*10**3 \t\t\t#discharge - cc/s\n", "depth = 4. \t\t\t#m\n", "d = 5. \t \t\t#cm\n", "g = 9.81 \t\t \t#m/s**2\n", "rho = 10.**3 \t\t\t#kg/m**3\n", "\t\t\t\n", "#calculations\n", "V1 = Q/(math.pi/4 *d**2) /100\n", "V2 = math.sqrt(2*g*(V1**2/(2*g) + depth))\n", "W = rho*Q*(V2-V1)/10**6\n", "\t\t\t\n", "#results\n", "print \"weight of water = %d N\"%(W)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "weight of water = 66 N\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.5 Page No : 116" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "#Initialization of variables\n", "g = 9.81 \t \t\t#m/s**2\n", "rho = 10.**3 \t\t\t#kg/m**3\n", "V = 50. \t\t \t#velocity - m/s\n", "u = 20. \t\t\t #m/s\n", "A = 6./10**4 \t\t\t#area - m**2\n", "angle = 180. \t\t\t#degrees\n", "\t\t\t\n", "#calculations\n", "Vr = V-u\n", "rq = rho*A*Vr\n", "Rx = -rq*(Vr*math.cos(math.radians(angle)) - Vr)\n", "Rx2 = -rho*A*V*(Vr*math.cos(math.radians(angle)) -Vr)\n", "power = Rx2*u\n", "\t\t\t\n", "#results\n", "print \"Force exetred on fluid = %d N\"%(Rx)\n", "print \" Force transferred in case 2 = %d N\"%(Rx2)\n", "print \" Power transferred in case 2 = %d kW\"%(power/1000)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Force exetred on fluid = 1080 N\n", " Force transferred in case 2 = 1800 N\n", " Power transferred in case 2 = 36 kW\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.6 Page No : 119" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "#Initialization of variables\n", "g = 9.81 \t\t\t#m/s**2\n", "rho = 10.**3 \t\t#kg/m**3\n", "Vr = 10. \t\t\t#m/s\n", "u = 8.5 \t\t\t#m/s\n", "A = 250./10**4 \t\t#m**2\n", "\t\t\t\n", "#calculations\n", "V = Vr-u\n", "Q = A*Vr\n", "R = rho*Q*V\n", "P = R*u\n", "eth = 1/(1+ V/(2*u))\n", "\t\t\t\n", "#results\n", "print \"Power required = %.3f kW\"%(P/1000)\n", "print \" Efficiency of jet propulsion = %.0f percent\"%(eth*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power required = 3.188 kW\n", " Efficiency of jet propulsion = 92 percent\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.7 Page No : 123" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "#Initialization of variables\n", "g = 9.81 \t\t\t#m/s**2\n", "rho = 10.**3 \t\t#kg/m**3\n", "v1 = 20. \t\t\t#m/s\n", "v2 = 5. \t\t\t#m/s\n", "r1 = 50./100 \t\t#cm\n", "r2 = 30./100 \t\t#cm\n", "a1 = 20. \t\t\t#degrees\n", "a2 = 80. \t\t\t#degrees\n", "N = 300. \t\t\t#rpm\n", "Q = 5. \t\t\t #m**3/s\n", "\t\t\t\n", "#calculations\n", "u1 = round(math.pi*2*r1*N/60,1)\n", "u2 = round(math.pi*2*r2*N/60,2)\n", "T = rho*Q*(r1*v1*math.cos(math.radians(a1)) - r2*v2*math.cos(math.radians(a2)))\n", "H = 1/g *(u1*v1*math.cos(math.radians(a1)) - u2*v2*math.cos(math.radians(a2)))\n", "power = rho*g*Q*H\n", "\t\n", " \n", "#results\n", "print \"torque = %d N m\"%(T)\n", "print \" Heat = %.1f m\"%(H)\n", "print \" Power = %d kW\"%(power/10**3)\n", "\n", "# Note :The answers given in textbook are a bit different due to rounding off error. please check using calculator." ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "torque = 45682 N m\n", " Heat = 29.2 m\n", " Power = 1434 kW\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.8 Page No : 124" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "#Initialization of variables\n", "g = 9.81 \t\t\t#m/s**2\n", "rho = 10.**3 \t\t#kg/m**3\n", "d1 = 0.05 \t\t\t#m\n", "d2 = 0.3 \t\t\t#m\n", "N = 1800. \t\t\t#rpm\n", "Q = 0.425/60 \t\t#m**3/s\n", "\t\t\t\n", "#calculations\n", "u1 = math.pi*d1*N/60\n", "u2 = math.pi*d2*N/60\n", "T = rho*Q*(d2*u2 - d1*u1)/2\n", "\t\t\t\n", "#results\n", "print \"Torque supplied = %.1f Nm\"%(T)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Torque supplied = 29.2 Nm\n" ] } ], "prompt_number": 10 } ], "metadata": {} } ] }