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{
"metadata": {
"name": "",
"signature": "sha256:bd33818d3448353cd987bb363aa4b45c6fc5ac2971d0999934915bf83d11a9cd"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 13 : Fluid Flow about Immersed Objects"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.1 Page No : 502"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\t\t\n",
"# variables\n",
"b = 50.;\t\t#ft\n",
"c = 7.;\t\t #ft\n",
"CL = 0.6;\t\t#lift coefficient\n",
"CD = 0.05;\t\t#drag coefficient\n",
"alpha = 7.;\t\t#degrees\n",
"V = round(150/0.681818);\t\t#coverting mph to fps\n",
"H = 10000.;\t\t#ft\n",
"rho = 0.001756;\t\t#slug/cuft\n",
"\n",
"# calculations \n",
"D = CD*b*c*rho*0.5*V**2;\n",
"hp = D*V/550;\n",
"L = CL*b*c*rho*0.5*V**2;\n",
"mu = 3.534*10**-7;\t\t#lb-sec/sqft\n",
"R = V*c*rho/mu;\n",
"a = math.sqrt(1.4*32.2*53.3*(23.4+459.6));\n",
"M = V/a;\n",
"\n",
"# results \n",
"print 'hp = %.f hp, L = %.2f lb, R = %d, M = %.3f'%(hp,L,round(R,-4),M);\n",
"\n",
"# note : answer is different because of rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"hp = 297 hp, L = 8923.99 lb, R = 7650000, M = 0.204\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.2 Page No : 511"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\t\t\n",
"# variables\n",
"l = 5.;\t\t#ft\n",
"d = 0.5;\t\t#ft\n",
"v = 1.;\t\t#fps\n",
"T = 60.;\t\t#degreeF\n",
"D = 0.04;\t\t#lb\n",
"k = 1./64;\t\t#model scale\n",
"\n",
"# calculations \n",
"nu = 0.00001217;\n",
"R = round(v*l/nu,-4);\n",
"Cf1 = 0.0020;\n",
"Cf2 = 0.0052;\n",
"Dx1 = round(2*Cf1*l*d*1.938*0.5*v**2,4);\n",
"Dx2 = round(2*Cf2*l*d*1.938*0.5*v**2,3) \n",
"delta1 = round(l*5.20/math.sqrt(R),2);\n",
"delta2 = l*0.38/(R**0.2);\n",
"V_0 = math.sqrt((v**2 /l)*(l*(1/k)));\n",
"R_p = V_0*l*(1/k)/nu;\n",
"Cf = 0.00185;\n",
"Dx = 2*Cf*l*d*(1/k)**2 *1.938*0.5*V_0**2;\n",
"Dw = D-Dx2;\n",
"Dw_p = (1/k)**2 *d*l*V_0**2 *Dw/(l*d);\n",
"D = round(Dw_p + Dx,-1);\n",
"\n",
"# results \n",
"print 'Total drag of the prototype = %d lb'%(D);\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Total drag of the prototype = 6280 lb\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13.3 Page No : 524"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# variables\n",
"c = 6.;\t\t#ft\n",
"b = 36.;\t\t#ft\n",
"AR1 = 6.;\t\t#aspect ratio\n",
"Cd = 0.0543;\t\t#drag coefficient\n",
"Cl = 0.960;\t\t#lift coefficient\n",
"alpha1 = 7.2;\t\t#degrees\n",
"AR2 = 8.;\n",
"\n",
"# calculations \n",
"#for aspect ratio = 8\n",
"CL = 0.960;\t\t#negligible change of lift coefficient\n",
"#for aspect ratio = 6\n",
"C_Di = Cl**2 /(math.pi*AR1);\n",
"#for aspect ratio = infinity\n",
"C_D0 = Cd - C_Di;\n",
"#for AR = 8\n",
"C_D = C_D0 + Cl**2 /(math.pi*AR2);\n",
"#for AR = 6\n",
"alpha_i = (180/math.pi)*Cl/(math.pi*AR1);\n",
"#for AR = infinty\n",
"alpha_0 = alpha1 - alpha_i;\n",
"#for AR = 8\n",
"alpha = alpha_0 + Cl/(AR2*math.pi) *(360/(2*math.pi));\n",
"\n",
"# results \n",
"print 'Lift coefficient = %.3f (negligible change of lift coefficient)'%(CL); #incorrect answer in the textbook\n",
"print 'Drag coefficient = %.4f'%(C_D);\n",
"print 'Angle of attack = %.1f degress'%(alpha);"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Lift coefficient = 0.960 (negligible change of lift coefficient)\n",
"Drag coefficient = 0.0421\n",
"Angle of attack = 6.5 degress\n"
]
}
],
"prompt_number": 3
}
],
"metadata": {}
}
]
}
|
