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현재 위치

Equivalent (or composite) roughness coefficient (Horton-Einstein Method)

작성자 Uploader : r.soi.5 작성일 Upload Date: 2018-09-04변경일 Update Date: 2018-09-05조회수 View : 328

Equivalent (or composite) roughness coefficient (Horton-Einstein Method)

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

Horton-Einstein method is based on an assumption that flow velocity in each patial cross section is identical to the mean flow velocity in the entire cross section.

ne = [ ∑ Pi*ni^(1.5) / P ]^(2/3)

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

Calculator below can be used to consider up to the fifth partial cross section.

*** 참고문헌[References] ***

ne = ((P1*n1^1.5+P2*n2^1.5+P3*n3^1.5+P4*n4^1.5+P5*n5^1.5)/(P1+P2+P3+P4+P5))^(2/3)


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

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현재 위치

Equivalent (or composite) roughness coefficient (Horton-Einstein Method)

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