{ "metadata": { "name": "", "signature": "sha256:ef96c69329d4d090ccb3995280a3d98afa4f31033dd69fab00ee6053f89763a8" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "CHAPTER09:OBLIGUE SHOCK AND EXPANSION WAVES" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E01 : Pg 302" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math\n", "M = 2.; # mach number\n", "h = 16000.; # altitude of the plane\n", "\n", "# the mach angle can be calculated from eq.(9.1) as\n", "mue = math.asin(1./M); # mach angle\n", "\n", "d = h/math.tan(mue);\n", "\n", "print\"The plane is ahead of the bystander by a distance of:\\nd =\",d/1000.,\"km\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The plane is ahead of the bystander by a distance of:\n", "d = 27.7128129211 km\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E02 : Pg 302" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "from math import pi, sin,cos\n", "M1 = 2.; # mach number\n", "p1 = 1.; # ambient pressure\n", "T1 = 288.; # ambient temperature\n", "theta = 20.*pi/180.; # flow deflection\n", "\n", "# from figure 9.9, for M = 2, theta = 20\n", "b = 53.4*pi/180.; # beta\n", "Mn_1 = M1*sin(b); # upstream mach number normal to shock\n", "\n", "# for this value of Mn,1 = 1.60, from Appendix B we have\n", "Mn_2 = 0.6684; # downstream mach number normal to shock\n", "M2 = Mn_2/sin(b-theta); # mach number downstream of shock\n", "p2 = 2.82*p1;\n", "T2 = 1.388*T1;\n", "\n", "# for M = 2, from appendix A we have\n", "p0_2 = 0.8952*7.824*p1;\n", "T0_1 = 1.8*T1;\n", "T0_2 = T0_1;\n", "\n", "print\"M2 =\",M2,\"\\np2 =\",p2,\"atm\",\"\\nT2 =\",T2,\"K\",\"\\np0,2 =\",p0_2,\"atm\",\"\\nT0,2 =\",T0_2,\"K\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "M2 = 1.214211418 \n", "p2 = 2.82 atm \n", "T2 = 399.744 K \n", "p0,2 = 7.0040448 atm \n", "T0,2 = 518.4 K\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E03 : Pg 305" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "from math import pi,sin\n", "b = 30.*pi/180.; # oblique shock wave angle\n", "M1 = 2.4; # upstream mach number\n", "\n", "# from figure 9.9, for these value of M and beta, we have\n", "theta = 6.5*pi/180.;\n", "\n", "Mn_1 = M1*sin(b); # upstream mach number normal to shock\n", "\n", "# from Appendix B\n", "pressure_ratio = 1.513;\n", "temperature_ratio = 1.128;\n", "Mn_2 = 0.8422;\n", "\n", "M2 = Mn_2/sin(b-theta);\n", "\n", "print\"theta =\",theta*180./pi,\"degrees\",\"\\np2/p1 =\",pressure_ratio,\"\\nT2/T1 =\",temperature_ratio,\"\\nM2 =\",M2" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "theta = 6.5 degrees \n", "p2/p1 = 1.513 \n", "T2/T1 = 1.128 \n", "M2 = 2.11210524521\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E04 : Pg 309" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "from math import pi,sin\n", "b = 35.*pi/180.; # oblique shock wave angle\n", "pressure_ratio = 3.; # upstream and downstream pressure ratio\n", "\n", "# from appendix B\n", "Mn_1 = 1.64;\n", "M1 = Mn_1/sin(b);\n", "\n", "print\"The upstream mach number is:\\nM =\",M1" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The upstream mach number is:\n", "M = 2.85925274482\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E05 : Pg 309" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "from math import pi,sin\n", "M1 = 3.;\n", "b = 40.*pi/180.;\n", "\n", "# for case 1, for M = 3, from Appendix B, we have\n", "p0_ratio_case1 = 0.3283;\n", "\n", "# for case 2\n", "Mn_1 = M1*sin(b);\n", "\n", "# from Appendix B\n", "p0_ratio1 = 0.7535;\n", "Mn_2 = 0.588;\n", "\n", "# from fig. 9.9, for M1 = 3 and beta = 40, we have\n", "theta = 22.*pi/180.;\n", "M2 = Mn_2/sin(b-theta);\n", "\n", "# from appendix B for M = 1.9; we have\n", "p0_ratio2 = 0.7674;\n", "p0_ratio_case2 = p0_ratio1*p0_ratio2;\n", "\n", "ratio = p0_ratio_case2/p0_ratio_case1;\n", "\n", "print\"Ans =\",ratio" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Ans = 1.76130338105\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E06 : Pg 310" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "from math import pi,sin,tan\n", "M1 = 5.;\n", "theta = 15.*pi/180.;\n", "gam = 1.4;\n", "\n", "# for these values of M and theta, from fig. 9.9\n", "b = 24.2*pi/180;\n", "Mn_1 = M1*sin(b);\n", "\n", "# from Appendix B, for Mn,1 = 2.05, we have\n", "p_ratio = 4.736;\n", "\n", "# hence\n", "c_d = 4.*tan(theta)/gam/(M1**2.)*(p_ratio-1.);\n", "\n", "print\"The drag coefficient is given by:\\ncd =\",c_d" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The drag coefficient is given by:\n", "cd = 0.114406649477\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E07 : Pg 311" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "from math import pi,sin,tan\n", "M1 = 3.5;\n", "theta1 = 10.*pi/180.;\n", "gam = 1.4;\n", "p1 = 101300.;\n", "T1 = 288.;\n", "b=1.;#\n", "# for these values of M and theta, from fig. 9.9\n", "b1 = 24.*pi/180.;\n", "Mn_1 = M1*sin(b);\n", "\n", "# from Appendix B, for Mn,1 = 2.05, we have\n", "Mn_2 = 0.7157;\n", "p_ratio1 = 2.32;\n", "T_ratio1 = 1.294;\n", "M2 = Mn_2/sin(b1-theta1);\n", "\n", "# now\n", "theta2 = 10.*pi/180.;\n", "\n", "# from fig. 9.9\n", "b2 = 27.3*pi/180.;\n", "phi = b2 - theta2;\n", "\n", "# from Appendix B\n", "p_ratio2 = 1.991;\n", "T_ratio2 = 1.229;\n", "Mn_3 = 0.7572;\n", "M3 = Mn_3/sin(b2-theta2);\n", "\n", "# thus\n", "p3 = p_ratio1*p_ratio2*p1;\n", "T3 = T_ratio1*T_ratio2*T1;\n", "\n", "print\"p3 =\",p3/1e5,\"x 10**5 N/m2\",\"\\nT3 =\",T3,\"K\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "p3 = 4.67916856 x 10**5 N/m2 \n", "T3 = 458.013888 K\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E08 : Pg 312" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "from math import pi,sin,tan\n", "M1 = 1.5; # upstream mach number\n", "theta = 15.*pi/180.; # deflection angle\n", "p1 = 1.; # ambient pressure in atm\n", "T1 = 288.; # ambient temperature\n", "\n", "# from appendix C, for M1 = 1.5 we have\n", "v1 = 11.91*pi/180.;\n", "\n", "# from eq.(9.43)\n", "v2 = v1 + theta;\n", "\n", "# for this value of v2, from appendix C\n", "M2 = 2.;\n", "\n", "# from Appendix A for M1 = 1.5 and M2 = 2.0, we have\n", "p2 = 1./7.824*1.*3.671*p1;\n", "T2 = 1./1.8*1.*1.45*T1;\n", "p0_1 = 3.671*p1;\n", "p0_2 = p0_1;\n", "T0_1 = 1.45*T1;\n", "T0_2 = T0_1;\n", "\n", "# from fig. 9.25, we have\n", "fml = 41.81; # Angle of forward Mach line\n", "rml = 30. - 15.; # Angle of rear Mach line\n", "\n", "print\"p2 =\",p2,\"atm\",\"\\nT2 =\",T2,\"K\",\"\\np0,2 =\",p0_2,\"atm\",\"\\nT0,2 =\",T0_2,\"K\",\"\\nAngle of forward Mach line =\",fml,\"degrees\",\"\\nAngle of rear Mach line =\",rml,\"degrees\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "p2 = 0.469197341513 atm \n", "T2 = 232.0 K \n", "p0,2 = 3.671 atm \n", "T0,2 = 417.6 K \n", "Angle of forward Mach line = 41.81 degrees \n", "Angle of rear Mach line = 15.0 degrees\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E09 : Pg 312" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math\n", "from math import pi\n", "M1 = 10.; # upstream mach number\n", "theta = 15.*pi/180.; # deflection angle\n", "p1 = 1.; # ambient pressure in atm\n", "# from appendix C, for M1 = 10 we have\n", "v1 = 102.3*pi/180.;\n", "# in region 2\n", "v2 = v1 - theta;\n", "# for this value of v2, from appendix C\n", "M2 = 6.4;\n", "# from Appendix A for M1 = 10 and M2 = 6.4, we have\n", "p2 = 1./(2355.)*1.*42440.*p1;\n", "print\"M2 =\",M2,\"\\np2 =\",p2,\"atm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "M2 = 6.4 \n", "p2 = 18.0212314225 atm\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E10 : Pg 315" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "M1 = 10; # upstream mach number\n", "theta = 15*math.pi/180; # deflection angle\n", "p1 = 1; # ambient pressure in atm\n", "\n", "# from fig 9.9, for M1 = 10 and theta = 15 we have\n", "b = 20*math.pi/180;\n", "Mn_1 = M1*math.sin(b);\n", "\n", "# from Appendix B, for Mn,1 = 3.42\n", "Mn_2 = 0.4552;\n", "M2 = Mn_2/math.sin(b-theta);\n", "p2 = 13.32*p1;\n", "\n", "# from Appendix A, for M1 = 10\n", "p0_2 = 0.2322*42440*p1;\n", "\n", "print\"M2 =\",M2,\"\\np2 =\",p2,\"atm\",\"\\np0,2 =\",p0_2/1e3,\"x 10**3 atm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "M2 = 5.22283426943 \n", "p2 = 13.32 atm \n", "p0,2 = 9.854568 x 10**3 atm\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E11 : Pg 316" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# All the quantities are expressed in SI units\n", "import math \n", "M1 = 3.; # upstream mach number\n", "theta = 5.*math.pi/180.; # deflection angle\n", "alpha = theta; # angle of attack\n", "gam = 1.4;\n", "\n", "# from appendix C, for M1 = 3 we have\n", "v1 = 49.76*math.pi/180.;\n", "\n", "# from eq.(9.43)\n", "v2 = v1 + theta;\n", "\n", "# for this value of v2, from appendix C\n", "M2 = 3.27;\n", "\n", "# from Appendix A for M1 = 3 and M2 = 3.27, we have\n", "p_ratio1 = 36.73/55.;\n", "\n", "# from fig. 9.9, for M1 = 3 and theta = 5\n", "b = 23.1*math.pi/180.;\n", "Mn_1 = M1*math.sin(b);\n", "\n", "# from Appendix B\n", "p_ratio2 = 1.458;\n", "\n", "# thus\n", "c_l = 2./gam/(M1**2.)*(p_ratio2-p_ratio1)*math.cos(alpha);\n", "\n", "c_d = 2./gam/(M1**2.)*(p_ratio2-p_ratio1)*math.sin(alpha);\n", "\n", "print\"The lift and drag coefficients are given by:\\ncl =\",c_l,\"\\ncd =\",c_d" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The lift and drag coefficients are given by:\n", "cl = 0.124948402826 \n", "cd = 0.0109315687729\n" ] } ], "prompt_number": 11 } ], "metadata": {} } ] }