F-DEMPack Tutorial 2: Annular pipe

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Before starting with this tutorial, the user is strongly encouraged to follow
 
Before starting with this tutorial, the user is strongly encouraged to follow
 
the [[D-DEMPack Tutorial 2: Conveyor belt]] to get a feeling of how the problem type works, and in particular the DEM section. This tutorial will focus mainly in the Fluid section and its particularities.
 
the [[D-DEMPack Tutorial 2: Conveyor belt]] to get a feeling of how the problem type works, and in particular the DEM section. This tutorial will focus mainly in the Fluid section and its particularities.
 +
  
 
==Geometry==
 
==Geometry==
Line 8: Line 9:
 
In this tutorial, a simple geometry was created for the sake of simplicity. The idea is to understand all the steps involved in the problem type. The user must start by downloading the file [[File:F DEMPack2 Tutorial 6.gid.zip]], which contains the geometry and mesh of the proposed geometry. This file has already created the groups that will be used in the simulation.
 
In this tutorial, a simple geometry was created for the sake of simplicity. The idea is to understand all the steps involved in the problem type. The user must start by downloading the file [[File:F DEMPack2 Tutorial 6.gid.zip]], which contains the geometry and mesh of the proposed geometry. This file has already created the groups that will be used in the simulation.
  
[[File:F-DEM_Tutorial6_Geometry.png|350px]]
+
[[File:F-DEM_Tutorial6_Geometry.png|300px]]
  
 
The geometry of study consists of an annular tube through which a flux of an intermediate viscosity mud passes. An inlet creating DEM particles with time is located in the base of the annular pipe.
 
The geometry of study consists of an annular tube through which a flux of an intermediate viscosity mud passes. An inlet creating DEM particles with time is located in the base of the annular pipe.
  
===DEM group===
 
 
The downloaded file has already created the groups that will be used in the simulation.
 
 
[[File:F-DEM_Tutorial6_Groups.jpg|350px]]
 
 
In this sample case, the following five groups were created: Dem_inlet, Fluid, Inlet, No_slip and Outlet. The lower circle (surface) would be the Inlet, the smaller one just on top of it was the DEM_Inlet, the circle at the top would represent the Outlet, the No_slip would be the walls of the cylinder and, finally, the volume named Fluid would constitute the mass of fluid.
 
  
 
==Materials==
 
==Materials==
The Materials section in F-DEMPack contains the material data for both DEM and
+
We will continue by defining the properties of the fluid in the simulation. We just have to click on the icon showing in the next figure to open the menus and in particular the Materials tab:
fluid elements. See the next figure for an overview of that section:
+
  
[[File:DEM 2 tutorial swimming materials section.png|300px]]
 
  
The DEM part is identical to D-DEMPack, and a full explanation of every aspect
 
in it can be found in the corresponding links given above. In this case,
 
though, an additional section for the Fluid part exists, where the user can
 
set the values of some fundamental fluid properties, as for example density,
 
viscosity, bulk modulus or rheological characteristics.
 
  
===DEM-FEM wall group===
+
To begin inserting the fluid properties, we go to Fluid>Water and unfold the Fluid submenu by clicking on the plus sign on the right of Water. A list of parameters to fill in will unfold. The next figure shows the details.
[[File:DEM 2 tutorial swimming DEM FEM group.png|300px]]
+
  
The parameters in this section are identical to those in the D-DEMPack problem
 
type, so no extra information is necessary in this case.
 
  
===Inlet DEM group===
+
==DEM Entities==
[[File:DEM 2 tutorial swimming DEM inlet group.png|300px]]
+
The file contains several entities and conditions in relation to the DEM part of the problem. As previouly said, they are already preassigned so the user does not have to bother and can concentrate on the fluid aspects and details of the simulation. Nevertheless, figures showing the details on the DEM parts will be added here for the sake of completion and as a reference should the user lose these settings or in the case of have any problem when loading the file.
  
See [[D-DEMPack Tutorial 2: DemPack 2.0]] for details. It is important to
+
===DEM group===
note that it is still not possible to create neither clusters nor
+
nanoparticles from an inlet entity. This aspect of the code is still under
+
development.
+
  
===DEM Initial Conditions===
+
The downloaded file has already created the groups that will be used in the simulation.
[[File:DEM 2 tutorial swimming DEM Initial Conditions.png|300px]]
+
  
This section is also identical to its counterpart in D-DEMPack, so no further
+
[[File:F-DEM_Tutorial6_Groups.jpg.png|300px]]
explanations are needed.
+
  
==Materials==
+
In this sample case, the following five groups were created: Dem_inlet, Fluid, Inlet, No_slip and Outlet. The lower circle (surface) would be the Inlet, the smaller one just on top of it was the DEM_Inlet, the circle at the top would represent the Outlet, the No_slip would be the walls of the cylinder and, finally, the volume named Fluid would constitute the mass of fluid.
The Materials section in F-DEMPack contains the material data for both DEM and
+
fluid elements. See the next figure for an overview of that section:
+
  
[[File:DEM 2 tutorial swimming materials section.png|300px]]
+
===DEM-FEM wall group===
  
The DEM part is identical to D-DEMPack, and a full explanation of every aspect
+
===Inlet DEM group===
in it can be found in the corresponding links given above. In this case,
+
though, an additional section for the Fluid part exists, where the user can
+
set the values of some fundamental fluid properties, as for example density,
+
viscosity, bulk modulus or rheological characteristics.
+
  
==DEM-Fluid Interaction Settings==
+
===DEM Initial Conditions===
Most of the interaction parameters between the DEM spheres and fluid are
+
inside the General Application Data section, whose overview is given next:
+
 
+
[[File:DEM 2 tutorial swimming general application data.png|450px]]
+
  
Some of the parameters in this tree are very straightforward, as for example
 
the duration time, the output delta time, the number of threads to use in
 
the simulation or the gravity vector. Others, though, carry a higher
 
difficulty and are mostly related to the way the two subdomains interact. A
 
deeper explanation of those parameters can be found in [[F-DEMPack2 manual]]. The previous screenshot has been given to the user as a reference as
 
well as a guide for choosing some default values that give good results in
 
this particular case. This tree also includes the Results section, which is pretty straightforward.
 
  
 
==Fluid==
 
==Fluid==
This section contains the information about the properties of the fluids, the
 
different existing fluid elements and, when necessary, their assigned
 
conditions. It also has some parameters in relation to the settings of the
 
fluid solver. The figure that follow shows an overview of this section:
 
  
[[File:DEM 2 tutorial swimming fluid menu.png|250px]]
 
  
The screenshot shows the chosen parameters in this example. The user is
 
encouraged to play a little bit to those values and see the results. In this
 
case a monolithic solver was chosen to get more accurate results but no
 
turbulence model was considered necessary. The linear solver parameters
 
require a much deeper understanding of the underlying theory and the
 
associated numerical methods and will not be discussed here, check for more
 
information. The default parameters in the problem type gave good results in
 
this particular case. Finally, the user can enter the desired computational
 
time step, which does not have to be too small as long as stable simulations
 
are obtained.
 
 
===Properties===
 
===Properties===
In this section, the user can create a Property related with each of the
 
fluids in the problem. In order to do this, the corresponding fluid must have
 
been previously created in the Materials section. The next picture shows the
 
process:
 
 
[[File:DEM 2 tutorial swimming Fluid Properties.png|250px]]
 
 
In this particular case, the Water default material was assigned to the
 
Property1, which is good enough in this sample simulation.
 
  
 
===Elements===
 
===Elements===
The user must specify the fluids that will be present in the problem, so the
 
next step is to assign the desired groups to the Fluid Elements. The process
 
is the same as in other tutorials. A screenshot is given next:
 
 
[[File:DEM 2 tutorial swimming Elements Fluid.png|250px]]
 
 
To finish the elements assignation, though, an additional step is
 
necessary. The user must specify the FEM element type to be used in the fluid
 
mesh and the corresponding Property. The next figure shows this:
 
 
[[File:DEM 2 tutorial swimming Elements Fluid Property.png|250px]]
 
 
In this case, the only available element in 3D is the tetrahedra, while the
 
chosen property was number 1, corresponding to the Water material.
 
  
 
===Conditions===
 
===Conditions===
We finish the process by assigning the necessary conditions to their
 
corresponding groups.
 
====Initial Conditions====
 
The fluid solver needs some initial conditions in the fluid to solve the
 
problem. The next figure shows the section:
 
 
[[File:DEM 2 tutorial swimming Initial Conditions.png|200px]]
 
 
For this simulation, an initial vertical value of 1m/s was assigned to the
 
mass of fluid inside the tube. In this case, no initial pressure was necessary.
 
  
 
====Boundary Conditions====
 
====Boundary Conditions====
*''Inlet velocity''
 
An inlet velocity is necessary in this simulation for a flow to exist in time
 
along the interior of the tube. See the next picture:
 
  
[[File:DEM 2 tutorial swimming inlet group.png|200px]]
 
  
A vertical constant flow of 1m/s entering the bottom opening of the tube was
+
==DEM-Fluid Interaction Settings==
chosen. No Outlet Pressure was needed in the simulation.
+
*''No-Slip''
+
The user must tell the program if there exists any relative velocity between
+
the fluid and the solid boundary. The capture that follows shows the section:
+
  
[[File:DEM 2 tutorial swimming No Slip.png|200px]]
 
 
For this example, a no-slip behaviour was given to the walls. If there had
 
been additional DEM-FEM entities, an Is-Slip behaviour could have been given
 
to them.
 
  
 
==Meshing and Running==
 
==Meshing and Running==
If the user has succesfully assigned to the corresponding groups all the
 
previous Properties, Elements and Conditions, the only thing that is still
 
missing is the computational mesh. As already said, all the messing
 
characteristics has been previously set in this problem, so the user has been
 
able to focus in the Fluid aspects of the problem type. So to mesh, hit Ctr-G
 
and enter a value of 0.02 and press OK. A global view of the resulting mesh
 
should be similar to this one:
 
  
[[File:DEM 2 tutorial swimming mesh.png|350px]]
 
 
On the other hand, the initial DEM spheres mesh should look like the
 
following:
 
 
[[File:DEM 2 tutorial swimming mesh DEM detail.png|350px]]
 
 
While the inlet surface mesh should be very similar to this:
 
 
[[File:DEM 2 tutorial swimming mesh DEM inlet detail.png|350px]]
 
  
 
==Results==
 
==Results==
Once a mesh is obtained and the file saved, the simulation can be run. To
 
start the computations, the user must only hit F5 and the simulation will begin.
 
The next four captures show the resulting simulation at different times:
 
 
[[File:DEM 2 tutorial swimming velocities1of4.png|300px]]
 
[[File:DEM 2 tutorial swimming velocities2of4.png|300px]]
 
[[File:DEM 2 tutorial swimming velocities3of4.png|300px]]
 
[[File:DEM 2 tutorial swimming velocities4of4.png|300px]]
 
 
The next figure shows the stationary pressure field in the fluid:
 
 
[[File:DEM 2 tutorial swimming fluid pressure.png|300px]]
 
 
The user can also make a cut in the mass of fluid and obtained a 2D view of
 
the velocity field in the fluid:
 
 
[[File:DEM 2 tutorial swimming fluid velocities.png|300px]]
 

Revision as of 16:12, 26 January 2017

Contents

Introduction

Before starting with this tutorial, the user is strongly encouraged to follow the D-DEMPack Tutorial 2: Conveyor belt to get a feeling of how the problem type works, and in particular the DEM section. This tutorial will focus mainly in the Fluid section and its particularities.


Geometry

The process should start by creating a new geometry from scratch, by modifying an existing one or by opening a finished one. It is assumed that the user already knows how to do this procedure so no details will be given about it.

In this tutorial, a simple geometry was created for the sake of simplicity. The idea is to understand all the steps involved in the problem type. The user must start by downloading the file File:F DEMPack2 Tutorial 6.gid.zip, which contains the geometry and mesh of the proposed geometry. This file has already created the groups that will be used in the simulation.

F-DEM Tutorial6 Geometry.png

The geometry of study consists of an annular tube through which a flux of an intermediate viscosity mud passes. An inlet creating DEM particles with time is located in the base of the annular pipe.


Materials

We will continue by defining the properties of the fluid in the simulation. We just have to click on the icon showing in the next figure to open the menus and in particular the Materials tab:


To begin inserting the fluid properties, we go to Fluid>Water and unfold the Fluid submenu by clicking on the plus sign on the right of Water. A list of parameters to fill in will unfold. The next figure shows the details.


DEM Entities

The file contains several entities and conditions in relation to the DEM part of the problem. As previouly said, they are already preassigned so the user does not have to bother and can concentrate on the fluid aspects and details of the simulation. Nevertheless, figures showing the details on the DEM parts will be added here for the sake of completion and as a reference should the user lose these settings or in the case of have any problem when loading the file.

DEM group

The downloaded file has already created the groups that will be used in the simulation.

F-DEM Tutorial6 Groups.jpg.png

In this sample case, the following five groups were created: Dem_inlet, Fluid, Inlet, No_slip and Outlet. The lower circle (surface) would be the Inlet, the smaller one just on top of it was the DEM_Inlet, the circle at the top would represent the Outlet, the No_slip would be the walls of the cylinder and, finally, the volume named Fluid would constitute the mass of fluid.

DEM-FEM wall group

Inlet DEM group

DEM Initial Conditions

Fluid

Properties

Elements

Conditions

Boundary Conditions

DEM-Fluid Interaction Settings

Meshing and Running

Results

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