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™¼„˜o°ŠÁ„¸É¥ª„´ ´¤ž¦³· š›·Í¦ŠÁ¸ ¥—šµœ„ȇº°¤„µ¦š¸É ŗo¤µ‹µ„„µ¦šÎ µŽÊε¦° 2 ®¦º° 3 Ĝ¤„µ¦ Colebrook and
White ˜nª· ›¸„µ¦Ánœœ¸Ê‹³Ž´Žo°œ¤µ„ —´Šœ´ÊœŸ¨‹µ„„µ¦¦oµŠÂ‹Îµ¨°Š šÎµÄ®o ŗo ¤„µ¦š¸Éŗo Ÿ¨—¸š¸É » —Áž}œ °ŠÁ µ
Á°Š‡º°¤„µ¦
0.9924 0.9345
1 / 5.0272 / 4.567 / 5.3326
2.0 log log log
3.7065 R e 3.827 Re 7.7918 208.815 Re
D D D
f
H H H § · § · § ·
§ · § ·
¨ ¸ ¨ ¸ ¨ ¸
¨ ¸ ¨ ¸
¨ ¸ ¨ ¸ ¨ ¸
© ¹ © ¹
© ¹ © ¹ © ¹
˜µ¦µŠš¸É 1 —Š¤„µ¦š¸ÉčoĜ„µ¦®µ‡nµÂ¢‡Á˜°¦r¦ŠÁ¸¥—šµœ
š¸É œ´ „ª·‹´¥ ¤„µ¦ nªŠ‡ªµ¤™¼„˜o °Š
1. Moody (1947)
1
6 3
4 10
0.0055 1 2 10
Re
f x
D
H § ·
§ ·
¨ ¸
¨ ¸
¨ ¸
© ¹ ¨ ¸
© ¹
Re 4000 - 108
/ D H 0 - 0.01
2. Churchill (1973)
0.9
1/0.869 / 7
3.70 Re
f D
e H § ·
¨ ¸
© ¹
0.9 1 / 7
2log 3.70 Re
D
f
H § ·
§ ·
¨ ¸ ¨ ¸
¨ ¸
© ¹
© ¹
-
3. Chen (1979)
1.1098
0.8981
/ 1 / 5.0452 5.8506
2log log
3.7065 Re 2.8257 Re
D D x
f
H H § · § ·
¨ ¸ ¨ ¸
¨ ¸ ¨ ¸
© ¹ © ¹
Re 4000 - 4.108
/ D H 0.0000005-0.05
4. Round (1980) 1 6.5
1.8log 0.27 Re D f
H § ·
¨ ¸
© ¹ -
5. Haaland (1983)
1.11 1 / 6.9
1.8log
3.70 Re
D
f
H § ·
§ ·
¨ ¸ ¨ ¸ ¨ ¸
© ¹ © ¹
Re 4000 - 108
/ D H 0.000005-0.05
6. Manadilli (1997) 0.983
1 / 95 96.82
2log
3.70 Re Re
D
f
H § ·
¨ ¸
© ¹
Re 5235 - 108
/ D H 0 - 0.05