{ "cells": [ { "cell_type": "markdown", "metadata": { "collapsed": true }, "source": [ "# Chapter 06:Incompressible viscous flow: A brief review" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex6.1:pg-226" ] }, { "cell_type": "code", "execution_count": 3, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Introduction to heat transfer by S.K.Som, Chapter 6, Example 1\n", "Umax in m/s is\n", "Umax= 1.6\n", "The shear stress T in N/m**2\n", "T= 64.0\n", "(dp/dx) in N/m**3 is\n", "X= -19200.0\n", "The Shear stress at a distance of 0.002m from the lower plate in N/m**2\n", "t= -57.6\n", "The shear stress at a distance of 0.002m from the upper plate in N/m**2\n", "t= 57.6\n", "The opposite signs in t represents the opposite directions.The plus sign is in the direction of flow and the minus sign is in the direction opposite to the flow \n", "The pressure drop over a distance of 2m in N/m**2 is\n", "deltaP= 38400.0\n" ] } ], "source": [ " \n", "import math\n", " \n", "print\"Introduction to heat transfer by S.K.Som, Chapter 6, Example 1\"\n", " #Oil of specific gravity 0.90 and dynamic viscosity (mu=0.1Pa*s) flows between two fixed plates kept 2*b=10mm apart,So b=5mm.\n", "#The average velocity is Uav=1.60m/s\n", "Uav=1.60;\n", "mu=0.1;\n", "b=0.005; #in metre\n", " #Umax is maximum velocity\n", " Umax=(3.0/2)*Uav\n", "print\"Umax in m/s is\"\n", "Umax=(3/2)*Uav\n", "print\"Umax=\",Umax\n", " #The shear stress at the plate is given by T=2*µ*(Umax/b)\n", "print\"The shear stress T in N/m**2\"\n", "T=2*mu*(Umax/b) \n", " #The shear sress at a distance from plate is given by t=y*(dp/dx)\n", "#(dp/dx)=X=-3*mu*(Uav/b**2)\n", "print\"T=\",T\n", "print\"(dp/dx) in N/m**3 is\"\n", "X=-3*mu*(Uav/b**2)\n", " #Taking modulus of X by multipying it with negative sign.\n", "print\"X=\",X\n", "print\"The Shear stress at a distance of 0.002m from the lower plate in N/m**2\"\n", "y=b-0.002;\n", "t=y*(X) #NOTE:Answer given in the book is incorrect (Calculation mistake)\n", "print\"t=\",t\n", "print\"The shear stress at a distance of 0.002m from the upper plate in N/m**2\"\n", "t=-y*(X) #NOTE:Answer given in the book is incorrect (Calculation mistake)\n", "print\"t=\",t\n", "print\"The opposite signs in t represents the opposite directions.The plus sign is in the direction of flow and the minus sign is in the direction opposite to the flow \"\n", " #deltaP is the pressure drop\n", "print\"The pressure drop over a distance of 2m in N/m**2 is\"\n", " #Since pressure drop is considered at a distance of 2m so L=2m\n", "L=2;\n", "deltaP=(-X)*L\n", "print\"deltaP=\",deltaP\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex6.3:pg-229" ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Introduction to heat transfer by S.K.Som, Chapter 6, Example 3\n", "The rate of change of pressure with respect to length in N/m**3\n", "X= 2000\n", "Flow rate(Q) in m**3/s is)\n", "Q= 0.00333333333333\n", "The viscosity of oil(mu)in kg/(m*s)\n", "mu= 0.0920388472731\n" ] } ], "source": [ " \n", "import math\n", " \n", "print\"Introduction to heat transfer by S.K.Som, Chapter 6, Example 3\"\n", " #Oil of specific gravity (sg)=0.90 is discharged at a rate(mdot)=3kg/s under a pressure difference dp=10KN/m**2 over a length dz=5m of a pipe having a diameter(D) of 50mm.\n", "dp=10*10**3; #in N/m**2\n", "dz=5;\n", "D=0.05; #in metre\n", "mdot=3;\n", "sg=0.90;\n", " #X=dp/dz is the rate of change of pressure\n", "print\"The rate of change of pressure with respect to length in N/m**3\"\n", "X=dp/dz\n", "print\"X=\",X\n", " #Flow rate is Q\n", "print\"Flow rate(Q) in m**3/s is)\"\n", "Q=mdot/(sg*10**3)\n", "print\"Q=\",Q\n", " #The viscosity of oil is mu=(pi*D**4*X)/(128*Q*dz)\n", "print\"The viscosity of oil(mu)in kg/(m*s)\"\n", "mu=(math.pi*D**4*X)/(128*Q)\n", "print\"mu=\",mu\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex6.7:pg-250 " ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Introduction to heat transfer by S.K.Som, Chapter 6, Example 7\n", "The maximum length of plate in m is \n", "L= 2.5\n", "The average skin friction coefficient is\n", "cfL= 1.328\n", "Drag force on one side of plate in N is\n", "Fd= 21.5136\n" ] } ], "source": [ " \n", "import math\n", " \n", "print\"Introduction to heat transfer by S.K.Som, Chapter 6, Example 7\"\n", " #A flat plate B=1.2m wide and of length L is kept parallel to a uniform stream of air of velocity Uinf=3m/s in a wind tunnel.\n", "Uinf=3;\n", "B=1.2;\n", " #If it is desired to have a laminar boundary layer only on the plate \n", "#Assume that the laminar flow exists up to a reynold number(ReL)=5*10**5.Take density of air as rhoair=1.2kg/m**3 and viscosity of air as nuair=1.5*10**-5 m**2/s.\n", "nuair=1.5*10**-5;\n", "rhoair=1.2;\n", "ReL=5*10**5;\n", " #For maximum length of the plate reynolds number is ReL=Uinf*L/nuair\n", "#so L=ReL*nuair/Uinf\n", "print\"The maximum length of plate in m is \"\n", "L=ReL*nuair/Uinf\n", "print\"L=\",L\n", " #The average skin friction coefficient is cfL=1.328/(ReL)**(1/2)\n", "print\"The average skin friction coefficient is\"\n", "cfL=1.328/(ReL)**(1/2)\n", "print\"cfL=\",cfL\n", " #Fd is drag force\n", "print\"Drag force on one side of plate in N is\"\n", "Fd=cfL*(rhoair*Uinf**2/2)*B*L\n", "print\"Fd=\",Fd\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex6.10:pg-268 " ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Introduction to heat transfer by S.K.Som, Chapter 6, Example 10\n", "Wind velocity(Uinf)in m/s is\n", "Uinf= 10\n", "Reynolds number is\n", "ReL= 4000000.0\n", "Friction coefficient is\n", "CbarfL= 0.0735645\n", "Drag force on one side of the plate per unit metre width in Newton is \n", "FD= 26.48322\n", "The turbulent boundary layer thickness at the trailing edge in metre is \n", "delta= 2.274\n" ] } ], "source": [ " \n", "import math\n", " \n", "print\"Introduction to heat transfer by S.K.Som, Chapter 6, Example 10\"\n", " #Wind at a speed of U=36km/hr blows over a flat plate of length,L=6m .If the density and kinematic viscosity of air are rho=1.2kg/m**3 and mu=1.5*10**-5m**2/s respectively.\n", "U=36;\n", "L=6;\n", "rho=1.2;\n", "mu=1.5*10**-5;\n", " #Wind velocity in m/s is Uinf\n", "print\"Wind velocity(Uinf)in m/s is\"\n", "Uinf=U*1000/3600\n", "print\"Uinf=\",Uinf\n", " #Reynolds number is given by ReL=L*Uinf/mu\n", "print\"Reynolds number is\"\n", "ReL=L*Uinf/mu\n", "print\"ReL=\",ReL\n", " #We consider that transition of boundary layer takes place from laminar to turbulent takes place at ReL=5*10**5.\n", "#Therfore the corresponding friction coefficient is given by CbarfL=(0.074-ReL**(1/5))-(1742/ReL)\n", "print\"Friction coefficient is\"\n", "CbarfL=(0.074/ReL**(1/5))-(1742/ReL)\n", "print\"CbarfL=\",CbarfL\n", " #Drag force on one side of the plate per unit metre width is given by FD=CbarfL*rho*Uinf**2*L/2\n", "print\"Drag force on one side of the plate per unit metre width in Newton is \"\n", "FD=CbarfL*rho*Uinf**2*L/2\n", "print\"FD=\",FD\n", " #The turbulent boundary layer thickness at the trailing edge is given by delta=L*(0.379/ReL**(1/5))\n", "print\"The turbulent boundary layer thickness at the trailing edge in metre is \"\n", "delta=L*(0.379/ReL**(1/5))\n", "print\"delta=\",delta\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n", "\n" ] } ], "metadata": { "kernelspec": { "display_name": "Python 2", "language": "python", "name": "python2" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 2 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython2", "version": "2.7.11" } }, "nbformat": 4, "nbformat_minor": 0 }