{ "metadata": { "name": "", "signature": "sha256:f2115f2ad7692dfe801ea214554c915af4da1fd1ef8995d6587f66bc81d26a08" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 9 : Forces on bodies immersed in fluids" ] }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 9.1 pageno : 166" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "rho = 1.2\n", "mu = 1.85/100000\n", "pi = 3.1428\n", "d = 3.\n", "v = 50.*1000/3600\n", "\n", "#calculation part 1\n", "Re = d*rho*v/mu\n", "\n", "#from chart of drag coeff. vs Re\n", "Cd = 0.2 #coeff. of drag\n", "Ad = pi*d**2/4. #projected area\n", "Fd = Ad*Cd*rho*v**2/2.\n", "print \"The drag force on sphere in N\",Fd \n", "\n", "#part 2\n", "v = 2.\n", "l = 0.25\n", "Re = l*v*rho/mu\n", "zi = 4*pi*(l**3*3./4/pi)**(2/3.)/6./l**2 #sphericity\n", "\n", "#using graph\n", "Cd = 2.\n", "Ad = l**2\n", "Fd = Ad*Cd*rho*v**2/2.\n", "print \"The drag force on cube in N\",Fd \n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The drag force on sphere in N 163.6875\n", "The drag force on cube in N 0.3\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 9.2 page no : 168" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "rho = 1.2\n", "mu = 1.85/100000\n", "pi = 3.1428\n", "g = 9.81\n", "d = 1.38\n", "t = 0.1 #thickness\n", "v = 30*1000/3600.\n", "T = 26.2 #Tension\n", "m = 0.51 #mass\n", "theta = 60.*pi/180.\n", "\n", "#calculation\n", "Fd = T*math.cos(theta)\n", "print \"Drag force in N: %.4f\"% Fd\n", "A = pi*d**2/4.\n", "Ad = A*math.cos(theta) #area component to drag\n", "Cd = 2*Fd/Ad/rho/v**2 #coeff of drag\n", "print \"The drag coefficient: %.4f\"% Cd \n", "Fg = m*g #force of gravity\n", "Fb = rho*pi*d**2/4.*t*g #buoyant force\n", "Fl = Fg-Fb+T*math.sin(theta)\n", "print \"The lift force in N : %.4f\"%Fl\n", "Al = A*math.sin(theta)\n", "Cl = 2*Fl/Al/rho/v**2\n", "print \"The coefficient of lift: %.4f\"%Cl \n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Drag force in N: 13.0909\n", "The drag coefficient: 0.4202\n", "The lift force in N : 25.9368\n", "The coefficient of lift: 0.4803\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 9.3 page no : 171" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "rhog = 1200. #density of glycerol\n", "mu = 1.45\n", "pi = 3.1428\n", "g = 9.81\n", "rhos = 2280. #density of sphere\n", "v = 0.04 #terminal velocity\n", "a = 2*mu*g*(rhos-rhog)/v**3./3./rhog**2 #a = Cd/2/Re\n", "\n", "#using graph of Cd/2/Re vs Re\n", "Re = 0.32\n", "d = Re*mu/v/rhog\n", "print \"Diameter of sphere in (m): %.4f\"%d \n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Diameter of sphere in (m): 0.0097\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 9.4 page no : 173" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "rhoa = 1.218 #density of air\n", "mu = 1.73/100000\n", "pi = 3.1428\n", "g = 9.81\n", "rhog = 1200.\n", "rhop = 2280. #density of polythene\n", "d = 0.0034 #diameter\n", "a = 4*d**3*(rhop-rhoa)*rhoa*g/3/mu**2 #a = Cd*Re**2\n", "\n", "#using graph of Cd*Re**2 vs Re\n", "Re = 2200.\n", "v = Re*mu/d/rhog\n", "print \"The terminal velocity in (m/s) %f\"%v \n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The terminal velocity in (m/s) 0.009328\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 9.6 page no : 177" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math \n", "\n", "# Initialization of Variable\n", "pi = 3.1428\n", "rho = 825\n", "mu = 1.21\n", "g = 9.81\n", "l = 0.02\n", "de = 0.02 #dia exterior\n", "di = 0.012 #dia interior\n", "\n", "# Initialization of Variable\n", "rho = 998. #density of water\n", "mu = 1.25/1000 #viscosity of water\n", "w = 100. #mass of water\n", "pi = 3.1428\n", "g = 9.81\n", "rhog = 2280. #density of glass\n", "wg = 60. #mass of glass\n", "d = 45.*10**-6 #diameter of glass sphere\n", "\n", "#claculation\n", "rhom = (w+wg)/(w/rho+wg/rhog) #density of mixure\n", "e = w/rho/(w/rho+wg/rhog) #volume fraction of watter\n", "\n", "#using charts\n", "zi = math.exp(-4.19*(1.-e))\n", "\n", "K = d*(g*rho*(rhog-rho)*zi**2/mu**2)**(1./3) #stoke's law coeff.\n", "print K\n", "if K<3.3:\n", " print \"settling occurs in stoke-s law range\"\n", " U = g*d**2*e*zi*(rhog-rhom)/18/mu\n", " print \"settling velocity in m/s: %f\"%U\n", "else:\n", " print \"settling does not occurs in stoke-s law range\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "0.504080734813\n", "settling occurs in stoke-s law range\n", "settling velocity in m/s: 0.000297\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "\n", "example 9.7 page no : 180" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "from numpy import linspace\n", "\n", "\n", "# Initialization of Variable\n", "rhog = 1200. #density of glycerol\n", "mu = 1.45 #viscosity of glycerol\n", "pi = 3.1428\n", "g = 9.81\n", "rhos = 2280. #density of sphere\n", "d = 8/1000.\n", "s = 0.\n", "uf = 0.8*0.026\n", "\n", "#calculation\n", "def intre():\n", " s = 0.\n", " u = linspace(0,uf,1000)\n", " for i in range(0,1000):\n", " y = ((pi/6*d**3*rhos*g-pi*d**3/6*rhog*g-0.5*pi*d**2/4*24*mu/d/rhog*rhog*u[i])/pi*6/d**3/rhos)**(-1)*uf/1000\n", " s = s+y\n", " a = s\n", " return a\n", "\n", "t = intre()\n", "print \"Time taken by particle to reach 80%% of its velocity in (s): %f\"%t\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Time taken by particle to reach 80% of its velocity in (s): 0.009020\n" ] } ], "prompt_number": 9 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [] } ], "metadata": {} } ] }