1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
|
{
"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": 16,
"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",
" \n",
" \n",
" \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": 17,
"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",
" \n",
" \n",
" \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
}
|