Memoirs of the faculty of engineering, Yamaguchi university

山口大学工学部

PISSN : 1345-5583
NCID : AN00244228

Back to Top

Memoirs of the faculty of engineering, Yamaguchi university Volume 66 Issue 2
published_at 2016-03

Consideration on the boundary condition for calculations of open channel flow

開水路流れの境界条件に関する検討
Nagano Hiroyuki
fulltext
930 KB
A040066000204.pdf
Descriptions
The reason given for the boundary condition of calculation open channel flow leaves some insufficiencies. Calculation for tranquil flow is done toward upstream with downstream boundary condi-tion for depth, the reason is explained as the influence of downstream water level relating to wave propa-gation. But it is logically wrong since the discussion is based on the equation of steady flow without un-steady term. Mathematically, we have only to give boundary condition where the water depth is fixed and to proceed the calculation from the boundary condition position. Also, since the steady flow can be found by solving the governing equation for unsteady flow with steady boundary condition, boundary condition of the depth for steady flow calculation can be given in the same manner as for the analysis using the characteristic curve method. Boundary condition for free surface is obtained directly by equating the normal components of the velocities of water particles on the surface and of free surface variation.
Creator Keywords
open channel flow
water level calculation
boundary condition
steady flow equation
unsteady flow equation
free surface boundary condition