Abstract
Experimental study on hydraulic excitation force and cavitation at concave of a pipe branch opening fitted on a conduit wall is presented.
Excitation force with a similar feature to cavity oscillation appears in a pipe branch, too. The excitation force was grapsed by model test detecting resonance under flow condition of fL/V=0.5, 1 and so on, where f, L and V mean frequency, branch pipe diameter and flow velocity. Countermeasure for the excitation will be to make a branch flow into the pipe branch from a flow past the branch opening, or to make an inflow to the flow past the branch opening from the pipe branch.
As for cavitation, attention should be paied to location of a branch. To locate a branch in a stagnation region that is caused by a partial opening gate makes it easier to attain a non-cavitation flow condition. A bellmouth opening works well to attain a non-cavitation condition in the stagnation region.
