Multiple Scales Analysis of Water Hammer Attenuation

Numerical Evaluating of effective and behavior of balancing reservoir of water hummer on water tunnels lining to turbine in concrete dams

In this paper by using numerical evaluation the effect of balancing drupes of water hammer on tunnels lining is considered. In case of not arrangment of these reservoirs, the tunnel lining will be damaged of cyclic powers of water hammer. In this research, function of balancing reservoir of water hammer on cover of tunnels to the barriers’ turbine is simulated by numerical methods and Plaxis 3D...

Experimental and Numerical Simulation of Water Hammer in Water Conveyance Pipeline and Effect of Surge Tower Pipe in Controlling this Phenomenon

Water hammer is one of the unsteady flows in urban water distribution networks, which has been of great importance due to the damage caused to the pipeline and has always been of interest to researchers. In this study, the phenomenon of water hammer due to the sudden closure of the valve in the downstream end has been investigated in a laboratory and using a numerical model. In the laboratory s...

New piezometer hammer and jack for easy installation and pulling out of the piezometer in drainage and ground water studies

Stability Analysis of a Strongly Displacement Time-Delayed Duffing Oscillator Using Multiple Scales Homotopy Perturbation Method

In the present study, some perturbation methods are applied to Duffing equations having a displacement time-delayed variable to study the stability of such systems. Two approaches are considered to analyze Duffing oscillator having a strong delayed variable. The homotopy perturbation method is applied through the frequency analysis and nonlinear frequency is formulated as a function of all the ...

Water hammer simulation by explicit central finite difference methods in staggered grids

Four explicit finite difference schemes, including Lax-Friedrichs, Nessyahu-Tadmor, Lax-Wendroff and Lax-Wendroff with a nonlinear filter are applied to solve water hammer equations. The schemes solve the equations in a reservoir-pipe-valve with an instantaneous and gradual closure of the valve boundary. The computational results are compared with those of the method of characteristics (MOC), a...