Performance characteristics of axial flow hydraulic turbine with a collection device in free surface flow field

2017 ◽  
Vol 112 ◽  
pp. 53-62 ◽  
Author(s):  
Yasuyuki Nishi ◽  
Genki Sato ◽  
Daishi Shiohara ◽  
Terumi Inagaki ◽  
Norio Kikuchi
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Axial Flow ◽  
Free Surface Flow ◽  
Hydraulic Turbine ◽  
Surface Flow ◽  
Performance Characteristics ◽  
Collection Device

421 Free Surface Flow Analysis of an Axial Flow Hydraulic Turbine with a Collection Device

2014 ◽  
Vol 2014.24 (0) ◽  
pp. 186-189
Author(s):  
Sou Hirama ◽  
Yasuyuki Nishi ◽  
Terumi Inagaki ◽  
Yanrong Li ◽  
Norio Kikuchi
Keyword(s):  
Free Surface ◽  
Flow Analysis ◽  
Axial Flow ◽  
Free Surface Flow ◽  
Hydraulic Turbine ◽  
Surface Flow ◽  
Collection Device

The Free Surface Flow Around a TLP

2010 ◽  
Author(s):  
A. Yalpaniyan ◽  
M. Goodarzi
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Turbulent Flow ◽  
Numerical Solution ◽  
Flow Pattern ◽  
Symmetry Plane ◽  
Free Surface Flow ◽  
Inviscid Flow ◽  
Surface Flow ◽  
Wave Heights

A TLP is a buoyant platform containing four cylindrical columns. The purpose of this study was to consider the effects of different model solvers in the numerical solution on the flow pattern around the TLP. The flow around the TLP was numerically simulated with inviscid, laminar, and turbulent solvers. Three Froude numbers were run for each case. There was a symmetry plane that allowed simulating just one half of the flow field. Therefore, two columns along the symmetry plane were considered in the results discussion. Beside the generated surface waves there was a pair of vortex behind each column none of them were actually symmetric. The vortex behind the first column significantly affected the flow pattern around the second one in the manner that the vortex behind the first column was larger than the next one. In all cases the outer vortex was larger than the inner one. The obtained results showed that the generated waves of the inviscid flow were smoother than the turbulent flow, and also those of the turbulent flow were smoother than the laminar ones. Compared to the mentioned results, the influence of the flow velocity on the wave heights was more significant.

Effect of the Flow Rate on Performance Characteristics of an Axial Flow Hydraulic Turbine with a Collection Device

2018 ◽  
Vol 2018.26 (0) ◽  
pp. 319
Author(s):  
Hiroto SASASHITA ◽  
Yasuyuki NISHI ◽  
Daishi SHIOHARA ◽  
Terumi INAGAKI ◽  
Norio KIKUCHI
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Hydraulic Turbine ◽  
Performance Characteristics ◽  
Collection Device

Performance Characteristics and Flow Field of Axial Flow Hydraulic Turbine in Shallow Open Channel

2018 ◽  
Vol 11 (4) ◽  
pp. 387-399
Author(s):  
Yasuyuki Nishi ◽  
Genki Sato ◽  
Daishi Shiohara ◽  
Terumi Inagaki ◽  
Norio Kikuchi
Keyword(s):  
Flow Field ◽  
Open Channel ◽  
Axial Flow ◽  
Hydraulic Turbine ◽  
Performance Characteristics

scholarly journals A study of the flow field of an axial flow hydraulic turbine with a collection device in an open channel

2019 ◽  
Vol 130 ◽  
pp. 1036-1048 ◽  
Author(s):  
Yasuyuki Nishi ◽  
Genki Sato ◽  
Daishi Shiohara ◽  
Terumi Inagaki ◽  
Norio Kikuchi
Keyword(s):  
Flow Field ◽  
Open Channel ◽  
Axial Flow ◽  
Hydraulic Turbine ◽  
Collection Device

A Method to Calculate Resistance of Ship Taking the Effect of Dynamic Sinkage and Trim and Viscosity of Fluid

2011 ◽  
Vol 121-126 ◽  
pp. 1849-1857
Author(s):  
Chao Bang Yao ◽  
Wen Cai Dong
Keyword(s):  
Boundary Layer ◽  
Free Surface ◽  
Flow Field ◽  
Indirect Method ◽  
Free Surface Flow ◽  
Field Resistance ◽  
Surface Flow ◽  
Equilibrium Equations ◽  
Sinkage And Trim ◽  
Hydrodynamic Equilibrium

A method is presented to calculate the resistance of a ship taking the effect of sinkage & trim and viscosity of fluid. The free surface flow field is evaluated by solving RANS equations with VOF method. The sinkage and trim are computed by hydrodynamic equilibrium equations. The method can be divided into direct and indirect method according to the way to calculate trim of ship. The software Fluent is used to implement this method. With dynamic mesh being used, the position of a ship is updated by the motion of “ship + boundary layer” grid zone. The present methods have been applied to the INSEAN2340 hull for different Froude numbers and are found to be efficient for evaluating the flow field, resistance, sinkage and trim.

Simulation of a Free Surface Flow over a Vertical Weir

2012 ◽  
Vol 256-259 ◽  
pp. 2616-2620
Author(s):  
Y. L. Liu ◽  
Y. Bai
Keyword(s):  
Numerical Simulation ◽  
Free Surface ◽  
Theoretical Analysis ◽  
Flow Field ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Navier Stokes ◽  
Numerical Software ◽  
Typical Time ◽  
Time Point

In this paper the numerical simulation of a free surface flow over a vertical weir with in turns of a scour pool and a small hump weir is presented. Since in this case few of calculative examples adds scour pool and small hump weir in the model, it is meaningful to compute this example using a numerical software which is named Fluent 6.3. The numerical method used consists of Navier–Stokes turbulence solver and k-ε model together with a VOF method and PISO algorithm in pave meshes. Thus, the sketches of flow fields on each typical time point and velocity distributions on each section on 16s are provided to describe flow field accurately. A very good quantitative consequence which accords with hydraulics theoretical analysis has been obtained.

scholarly journals Stagnant peaked free surface released at a sloping beach

2021 ◽  
Vol 127 (1) ◽  
Author(s):  
Peder A. Tyvand ◽  
Jonas Kristiansen Nøland
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Single Wave ◽  
Initial Flow ◽  
Acceleration Field ◽  
Zero Velocity ◽  
Run Up ◽  
Sloping Beach

AbstractA stagnant free-surface flow is an instantaneous flow field of pure acceleration with zero velocity and a deformed surface. There exists a potential-flow acceleration field. With zero velocity and the acceleration field given, there is a limiting free-surface position which possesses one peak at its point of highest elevation. By complex analysis, it can be shown that the surface peak has a right angle. We elaborate on an elementary model of two-dimensional stagnant free-surface flow with a peak. Our model may serve to describe a situation of maximal single-wave run-up with a given energy at a uniformly sloping beach. The highest possible run-up of an incoming solitary wave corresponds to zero kinetic energy. It encompasses an idealized situation where the kinetic wave energy is converted into potential energy in a water mass piling up along the slope to become stagnant at one single moment. Multipoles with singularities outside the fluid domain may give rise to a smooth and gradual deceleration needed for a non-breaking run-up process. A pair of dipoles with an orientation perpendicular to a given slope represents the stagnant acceleration fields with the highest surface peak spatially concentrated along the slope. Thereby, a one-parameter family of surface shapes is constituted, only dependent on the slope angle. The initial flow field, the initial free surface, the initial isobars and the geometric parameters are all calculated for different slope angles.

Discharge and flow field of the circular channel along the side weir

2015 ◽  
Vol 42 (4) ◽  
pp. 273-280 ◽  
Author(s):  
Hamed Azimi ◽  
Hazhar Hadad ◽  
Zakarya Shokati ◽  
Mohammad Sajad Salimi
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Circular Channel ◽  
Side Weir ◽  
Stream Surface ◽  
Discharge Coefficients ◽  
Drainage Networks ◽  
Surface Variation

The side weir is one of the most important hydraulic structures that is used by hydraulic engineers for adjusting and controlling flow in urban waste collection systems, irrigation and drainage networks. In this study, an equation is proposed for computing side weir discharge located on circular channels. The equation computes the side weir discharge with sufficient accuracy. Then, the RNG k–ε turbulence model is used for simulating the turbulence of the flow field and the free surface flow variations are modeled using volume of fluid scheme. Comparing experimental results with numerical simulations indicates acceptable accuracy of the numerical model. Also, the side weir discharge coefficients, flow free surface variation, behavior of dividing stream surface and variations of stagnation point height for different discharges within a circular channel along a side weir were examined.

Hydraulic Investigations on Free Surface Flow of ADS Windowless Target

2017 ◽  
Author(s):  
Chen Hu
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Flow Velocity ◽  
Simulation Models ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Water Model ◽  
Critical System ◽  
Inlet Flow ◽  
Outlet Pressure

The formation and control of free surface flow is one of the most essential parts in the studies of windowless target in acceleration driven sub-critical system (ADS). Water model experiments and 360° full scale three dimensional simulations are conducted in this page. The free surface motion is significantly affected by the inlet flow velocity and outlet pressure. The length of free surface decrease in the second order with the inlet flow velocity, while it decreases linearly with the outlet pressure. The structure and feature of flow field are investigated. The results show that the free surface is vulnerable to the vortex movement. Transient simulations are performed with volume of fluid (VOF) method, large eddy simulation (LES) and the pressure implicit with splitting of operators (PISO) algorithm. The simulation results agree qualitatively well with the experimental data related to both free surface flow and flow field. These simulation models and methods are proved to be practicable in the hydraulic simulations of liquid heavy metal target.

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