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현재 위치

Equivalent (or composite) roughness coefficient (Pavloskii Method)

작성자 Uploader : r.soi.5 작성일 Upload Date: 2018-09-04변경일 Update Date: 2018-09-05조회수 View : 297

Equivalent (or composite) roughness coefficient (Pavloskii Method)

When the roughness varies partially along the wetted perimeter, the equivalent roughness should be used.

Pavloskii method is based on an assumption that the sum of friction resisting against flow in each patial cross section is identical to the friction in the entire cross section.

ne = [ ∑ Pi*ni^(2) / P ]^(1/2)

ne : composite roughness
Pi : length of wetted perimeter of the i-th cross section
ni : roughness of the i-th cross section
P : length of wetted perimeter of the entire cross section

Calculator below can be used to consider up to the 5-th cross section.

*** 참고문헌[References] ***

ne = ((P1*n1^2+P2*n2^2+P3*n3^2+P4*n4^2+P5*n5^2)/(P1+P2+P3+P4+P5))^(1/2)


변수명 Variable	변수값 Value	변 수 설 명 Description of the variable

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현재 위치

Equivalent (or composite) roughness coefficient (Pavloskii Method)

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