28:
110:
leading firms built this type of gun but it proved unpopular and most were returned to the manufacturers for large bore barrels. To most shooters perhaps the idea of placing a 12 bore cartridge into a 20 bore barrel was too "explosive". Complete functioning examples are now rare, though they are still not highly sought after.
76:
The reason for this phenomenon is that fluid streamlines cannot abruptly change direction. In the case of both the free jet and the sudden pipe diameter change, the streamlines are unable to closely follow the sharp angle in the pipe/tank wall. The converging streamlines follow a smooth path, which
109:
of sporting shotguns tapered very heavily from the breech to the muzzle. Thus a gun with a 12 bore breech would have a 20 bore muzzle. The idea was to retain the advantages of a heavy-hitting large bore shotgun while retaining the lesser recoil and easy maneuverability of a small bore. Several
20:
54:, 1643). It is a place where the cross section area is minimal. The maximum contraction takes place at a section slightly downstream of the orifice, where the jet is more or less horizontal.
57:
The effect is also observed in flow from a tank into a pipe, or a sudden contraction in pipe diameter. Streamlines will converge just downstream of the diameter change, and a region of
42:
is the point in a fluid stream where the diameter of the stream is the least, and the fluid velocity is at its maximum, such as in the case of a stream issuing out of a
128:
The typical value may be taken as 0.611 for a sharp orifice (concentric with the flow channel). The smaller the value, the greater the effect the vena contracta has.
35:
Dam, the river is forced to narrow by a concrete bridge support. Flow separation is evident at the sharp bend, just above the vena contracta
118:
The coefficient of contraction is defined as the ratio between the area of the jet at the vena contracta and the area of the orifice.
271:
240:
157:
89:, where it describes the smallest area of the blood flow jet as it exits a heart valve. This corresponds to the
90:
290:
65:
51:
137:
197:
8:
201:
61:
occurs at the sharp corner of the diameter change and extends past the vena contracta.
182:
267:
246:
236:
213:
205:
86:
32:
19:
58:
250:
284:
217:
27:
47:
106:
209:
102:
183:"Velocity Coefficients For Free Jets From Sharp-Edged Orifices"
43:
77:
results in the narrowing of the jet (or primary pipe flow).
266:. Cambridge University Press. p. 11 and Exercise 1.3.
93:
calculated for heart valves using the continuity equation.
235:. Kidlington, Oxford: Butterworth-Heinemann. p. 512.
64:
The formation of the vena contracta can be seen in the
230:
158:"What is Venturimeter ? Construction and Working"
101:Vena Contracta was a term used by several English
282:
233:Free-surface flow. Environmental fluid mechanics
85:Measurement of the vena contracta is useful in
264:Fluid Mechanics, a short course for physicists
155:
113:
105:builders of the 19th and 20th Century. The
125:= Area at vena contracta/Area of orifice.
261:
231:Katopodes, Nikolaos D. (21 August 2018).
180:
26:
18:
283:
80:
13:
14:
302:
16:Narrowest point in a fluid stream
224:
181:Lienhard, J. H. (1984-03-01).
174:
149:
71:
1:
190:Journal of Fluids Engineering
143:
156:Eligoprojects (2018-10-30).
91:effective orifice area (EOA)
7:
131:
96:
10:
307:
114:Coefficient of contraction
262:Falkovich, G. (2011).
52:Evangelista Torricelli
36:
24:
138:Borda-Carnot equation
30:
22:
202:1984ATJFE.106...13L
37:
25:
273:978-1-107-00575-4
242:978-0-12-816251-4
210:10.1115/1.3242391
298:
277:
255:
254:
228:
222:
221:
187:
178:
172:
171:
169:
168:
153:
87:echocardiography
81:Echocardiography
31:Just beyond the
306:
305:
301:
300:
299:
297:
296:
295:
291:Fluid mechanics
281:
280:
274:
258:
243:
229:
225:
185:
179:
175:
166:
164:
154:
150:
146:
134:
124:
116:
99:
83:
74:
33:Swartswood Lake
17:
12:
11:
5:
304:
294:
293:
279:
278:
272:
257:
256:
241:
223:
173:
147:
145:
142:
141:
140:
133:
130:
122:
115:
112:
98:
95:
82:
79:
73:
70:
59:separated flow
40:Vena contracta
23:Vena contracta
15:
9:
6:
4:
3:
2:
303:
292:
289:
288:
286:
275:
269:
265:
260:
259:
252:
248:
244:
238:
234:
227:
219:
215:
211:
207:
203:
199:
195:
191:
184:
177:
163:
162:Eligoprojects
159:
152:
148:
139:
136:
135:
129:
126:
119:
111:
108:
104:
94:
92:
88:
78:
69:
67:
62:
60:
55:
53:
49:
45:
41:
34:
29:
21:
263:
232:
226:
196:(1): 13–17.
193:
189:
176:
165:. Retrieved
161:
151:
127:
120:
117:
100:
84:
75:
66:venturimeter
63:
56:
39:
38:
107:gun barrels
72:Explanation
251:1049568159
167:2019-12-17
144:References
218:0098-2202
285:Category
132:See also
97:Shotguns
198:Bibcode
103:shotgun
48:orifice
270:
249:
239:
216:
44:nozzle
186:(PDF)
268:ISBN
247:OCLC
237:ISBN
214:ISSN
50:). (
206:doi
194:106
287::
245:.
212:.
204:.
192:.
188:.
160:.
68:.
276:.
253:.
220:.
208::
200::
170:.
123:c
121:C
46:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.