Lifting Dam CFD Simulation, Ansys Fluent Training

Lifting Dam Project Description

Numerical simulation of lifting dam has been performed using Ansys Fluent software in this project. The VOF model is used to simulate two fluid phases, and the purpose of this project is to investigate the changes in the free surface of the fluid over time. Two models are reviewed in this project. In the first model, the flow continues its path after crossing the dam, but in the second model, it encounters an obstacle.

Geometry & Mesh

The two-dimensional geometry of this project has been produced with Spaceclaim software. The length of the computational area is 70 mm, and its height is 40 mm.

The meshing of these geometries has been done using Ansys Meshing software. The mesh type is unstructured in all of the computational domains. The element number for case 1 is equal to 86611 and for case 2 is equal to 132614.

Lifting Dam CFD Simulation Settings

We consider several assumptions to simulate the present model:

1. Due to the incompressibility of the flow, the pressure-based solver method has been selected.
2. The simulation is transient.
3. The gravity effect is considered equal to -9.81 m.s^-1on Y-axis

The Laminar viscous model has been used to solve the flow field equations, and the pressure-velocity coupling scheme is SIMPLE. The second-order upwind discretization method has been used for momentum and PRESTO! For the pressure discretization.

The following tables represent a summary of the defining steps of the problem in this project and its solution:

Models
Multiphase
	Homogeneous model	Volume of fluid
	Number of Eulerian phases	2(air& water)
	Interface modeling	Sharp Interfacial
	Formulation	explicit
	Body force formulation	Implicit body force
Viscous		Laminar

Material Properties
Air
Density	1.225
viscosity	1.7894e-05
water-liquid
Density	998.2
viscosity	0.001003

Methods
Pressure-Velocity Coupling		SIMPLE
	Pressure	PRESTO!
	Momentum	Second-order upwind
	Volume fraction

Initialization
Initialization methods		Standard
Patch	Phase	Phase2
	Variable	Volume Fraction
	Registers to patch	Region_0
	Value	1

Run calculation
Time advancement	Type	adaptive
Parameters
	Initial time step size	0.0005
Settings	Minimum time step size	0.0005
	Maximum time step size	0.0005
	Time step size	2000

Results

In this simulation, the free surface of the fluid when the dam is opened is investigated. After the solution process is completed, contours of velocity, pressure, and volume fraction are extracted.  It is observed that in the second case after the flow hits the fluid barrier, reaches a relatively high altitude, which is due to the high kinetic energy in the initial moments.

[/vc_column_text]