F-DEMPack Tutorial 1: Curved pipe

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==Introduction==
 
==Introduction==
 
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: DemPack 2.0]] 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 [[G-DEMPack Tutorial 1: 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 user must start by downloading the [[File:D DEMPack2 Tutorial 4.gid.zip]] file. This file has already created the groups that will be used in the simulation. It has also already
+
The user must start by downloading [http://kratos-wiki.cimne.upc.edu/images/0/0b/D_DEMPack2_Tutorial_4.gid.zip Fluid-DEMPack_Tutorial]. This file has already created the groups that will be used in the simulation. It has also already assigned the DEM groups, as well as the mesh sizes. Once loaded into GiD, the F-DEMPack problemtype must be loaded from the Data Menu.
assigned the DEM groups, as well as the mesh sizes for all groups.
+
 
  
 
==Geometry==
 
==Geometry==
Line 10: Line 10:
 
of water, as well as an inlet creating DEM particles with time. This geometry
 
of water, as well as an inlet creating DEM particles with time. This geometry
 
can be observed in the picture that follows:
 
can be observed in the picture that follows:
 +
 
[[File:DEM 2 tutorial swimming geometry.png|350px]]
 
[[File:DEM 2 tutorial swimming geometry.png|350px]]
  
Line 19: Line 20:
 
group by different entities that the user is expected to find in the file
 
group by different entities that the user is expected to find in the file
 
available for downloading.
 
available for downloading.
FOTO GRUPOS
+
 
 +
[[File:DEM 2 tutorial swimming groups.png|350px]]
  
 
==DEM Entities==
 
==DEM Entities==
Line 29: Line 31:
 
user lose these settings or in the case of have any problem when loading the
 
user lose these settings or in the case of have any problem when loading the
 
file.
 
file.
===DEM group:===
+
===DEM group===
 
[[File:DEM 2 tutorial swimming DEM group.png|400px]]
 
[[File:DEM 2 tutorial swimming DEM group.png|400px]]
  
 
The FEM2DEM mesher was used to obtain this initial mesh of DEM spheres. See
 
The FEM2DEM mesher was used to obtain this initial mesh of DEM spheres. See
[[D-DEMPack Tutorial 3: DEM Meshers]] for a reference on the different meshers in the program. The
+
[[G-DEMPack Tutorial 3: DEM Meshers]] for a reference on the different meshers in the program. In this case, the
diameter of the elements is of 2mm with no variance. The element type is
+
chosen distribution of diameters for the elements is of 2mm with no variance.
standard. The user can also use the nanoparticle. See [[F-DEMPack2 manual]]
+
for more details.
+
  
===Inlet DEM group:===
+
===DEM-FEM wall group===
 +
[[File:DEM 2 tutorial swimming DEM FEM group.png|300px]]
 +
 
 +
The parameters in this section are identical to those in the G-DEMPack problem
 +
type, so no extra information is necessary in this case.
 +
 
 +
===Inlet DEM group===
 
[[File:DEM 2 tutorial swimming DEM inlet group.png|300px]]
 
[[File:DEM 2 tutorial swimming DEM inlet group.png|300px]]
  
See [[D-DEMPack Tutorial 2: DemPack 2.0]] for details. It is important to
+
See [[G-DEMPack Tutorial 2: DemPack 2.0]] for details. It is important to
 
note that it is still not possible to create neither clusters nor
 
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
 
nanoparticles from an inlet entity. This aspect of the code is still under
 
development.
 
development.
  
===DEM-FEM wall group:===
+
===DEM Initial Conditions===
[[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.
+
 
+
===DEM Initial Conditions:===
+
 
[[File:DEM 2 tutorial swimming DEM Initial Conditions.png|300px]]
 
[[File:DEM 2 tutorial swimming DEM Initial Conditions.png|300px]]
  
This section is also identical to its counterpart in D-DEMPack, so no further
+
This section is also identical to its counterpart in G-DEMPack, so no further
 
explanations are needed.
 
explanations are needed.
  
Line 64: Line 64:
 
[[File:DEM 2 tutorial swimming materials section.png|300px]]
 
[[File:DEM 2 tutorial swimming materials section.png|300px]]
  
The DEM part is identical to D-DEMPack, and a full explanation of every aspect
+
The DEM part is identical to G-DEMPack, and a full explanation of every aspect
 
in it can be found in the corresponding links given above. In this case,
 
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
 
though, an additional section for the Fluid part exists, where the user can
Line 73: Line 73:
 
Most of the interaction parameters between the DEM spheres and fluid are
 
Most of the interaction parameters between the DEM spheres and fluid are
 
inside the General Application Data section, whose overview is given next:
 
inside the General Application Data section, whose overview is given next:
FOTO GAD
+
 
 +
[[File:DEM 2 tutorial swimming general application data.png|450px]]
 +
 
 
Some of the parameters in this tree are very straightforward, as for example
 
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 duration time, the output delta time, the number of threads to use in
Line 87: Line 89:
 
conditions. It also has some parameters in relation to the settings of the
 
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:
 
fluid solver. The figure that follow shows an overview of this section:
FOTO MENU FLUID
+
 
 +
[[File:DEM 2 tutorial swimming fluid menu.png|250px]]
 +
 
 
The screenshot shows the chosen parameters in this example. The user is
 
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
 
encouraged to play a little bit to those values and see the results. In this
Line 103: Line 107:
 
been previously created in the Materials section. The next picture shows the
 
been previously created in the Materials section. The next picture shows the
 
process:
 
process:
FOTO PROPERTIES FLUID
+
 
 +
[[File:DEM 2 tutorial swimming Fluid Properties.png|250px]]
 +
 
 
In this particular case, the Water default material was assigned to the
 
In this particular case, the Water default material was assigned to the
 
Property1, which is good enough in this sample simulation.
 
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
 
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
 
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:
 
is the same as in other tutorials. A screenshot is given next:
FOTO ELEMENTS FLUID
+
 
 +
[[File:DEM 2 tutorial swimming Elements Fluid.png|250px]]
 +
 
 +
*''Important remarks''
 +
**'''Make sure a property has been created before assigning the fluid element.'''
 +
 
 
To finish the elements assignation, though, an additional step is
 
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
 
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:
 
mesh and the corresponding Property. The next figure shows this:
FOTO ELEMENTS FLUID PROPERTY
+
 
 +
[[File:DEM 2 tutorial swimming Elements Fluid Property.png|250px]]
 +
 
 
In this case, the only available element in 3D is the tetrahedra, while the
 
In this case, the only available element in 3D is the tetrahedra, while the
 
chosen property was number 1, corresponding to the Water material.
 
chosen property was number 1, corresponding to the Water material.
 +
 
===Conditions===
 
===Conditions===
 
We finish the process by assigning the necessary conditions to their
 
We finish the process by assigning the necessary conditions to their
Line 123: Line 138:
 
The fluid solver needs some initial conditions in the fluid to solve the
 
The fluid solver needs some initial conditions in the fluid to solve the
 
problem. The next figure shows the section:
 
problem. The next figure shows the section:
FOTO INITIAL CONDITIONS
+
 
 +
[[File:DEM 2 tutorial swimming Initial Conditions.png|200px]]
 +
 
 
For this simulation, an initial vertical value of 1m/s was assigned to the
 
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.
 
mass of fluid inside the tube. In this case, no initial pressure was necessary.
 +
 
====Boundary Conditions====
 
====Boundary Conditions====
 +
*''Important remarks''
 +
**'''Make sure that the whole fluid boundary has some fluid condition applied. Each surface of the fluid external skin must be either Inlet, Outlet, Slip or No-slip.'''
 +
**'''Make sure that entities not belonging to the external skin are NOT selected when applying the fluid boundary conditions.'''
 +
 
*''Inlet velocity''
 
*''Inlet velocity''
 
An inlet velocity is necessary in this simulation for a flow to exist in time
 
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:
 
along the interior of the tube. See the next picture:
FOTO INLET
+
 
 +
[[File:DEM 2 tutorial swimming inlet group.png|200px]]
 +
 
 
A vertical constant flow of 1m/s entering the bottom opening of the tube was
 
A vertical constant flow of 1m/s entering the bottom opening of the tube was
chosen. Also, fixity was set for the three axis. No Outlet Pressure was needed
+
chosen.  
in the simulation.
+
 
*''No-Slip''
 
*''No-Slip''
 
The user must tell the program if there exists any relative velocity between
 
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:
 
the fluid and the solid boundary. The capture that follows shows the section:
FOTO NO-SLIP
+
 
 +
[[File:DEM 2 tutorial swimming No Slip.png|200px]]
 +
 
 
For this example, a no-slip behaviour was given to the walls. If there had
 
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
 
been additional DEM-FEM entities, an Is-Slip behaviour could have been given
 
to them.
 
to them.
 +
*''Outlet pressure''
 +
Note that outlet pressure can be assigned to Points, Lines or Surfaces.
 +
 +
Choose which one you need before creating a new group.
 +
The user will create a new group named outlet and assign the upper circular surface to it. This surface represents the exit of the pipe.
 +
With the outlet created, it can be then assigned in the Outlet Pressure tab. The value of the pressure can be chosen. Typically 0.0.
 +
 
==Meshing and Running==
 
==Meshing and Running==
 
If the user has succesfully assigned to the corresponding groups all the
 
If the user has succesfully assigned to the corresponding groups all the
Line 149: Line 181:
 
and enter a value of 0.02 and press OK. A global view of the resulting mesh
 
and enter a value of 0.02 and press OK. A global view of the resulting mesh
 
should be similar to this one:
 
should be similar to this one:
FOTO MESH GLOBAL
+
 
 +
[[File:DEM 2 tutorial swimming mesh.png|350px]]
 +
 
 
On the other hand, the initial DEM spheres mesh should look like the
 
On the other hand, the initial DEM spheres mesh should look like the
 
following:
 
following:
FOTO INITIAL DEM MESH
+
 
 +
[[File:DEM 2 tutorial swimming mesh DEM detail.png|350px]]
 +
 
 
While the inlet surface mesh should be very similar to this:
 
While the inlet surface mesh should be very similar to this:
FOTO INLET DEM
+
 
 +
[[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
 
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.
 
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:
 
The next four captures show the resulting simulation at different times:
FOTO 4 VELOCITIES POST
+
 
 +
[[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:
 
The next figure shows the stationary pressure field in the fluid:
FOTO FLUID PRESSURE POST
+
 
 +
[[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 user can also make a cut in the mass of fluid and obtained a 2D view of
the velocity field in the fluid.
+
the velocity field in the fluid:
 +
 
 +
[[File:DEM 2 tutorial swimming fluid velocities.png|300px]]
 +
 
 +
 
 +
==Additional DEM Tutorials==
 +
Other tutorials can be found [http://kratos-wiki.cimne.upc.edu/index.php/DEMPack_Tutorials here].

Latest revision as of 10:33, 19 November 2018

Contents

Introduction

Before starting with this tutorial, the user is strongly encouraged to follow the G-DEMPack Tutorial 1: 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 user must start by downloading Fluid-DEMPack_Tutorial. This file has already created the groups that will be used in the simulation. It has also already assigned the DEM groups, as well as the mesh sizes. Once loaded into GiD, the F-DEMPack problemtype must be loaded from the Data Menu.


Geometry

The geometry of study consists of a curved tube through which a flux of water passes. Additionally, an initial mass of DEM elements exists inside the mass of water, as well as an inlet creating DEM particles with time. This geometry can be observed in the picture that follows:

DEM 2 tutorial swimming geometry.png

The geometry has five groups, as seen in the next picture. They consist of a sphere made up of DEM elements, placed at the middle of the tube, a cuadrilaterial inlet of DEM spheres near the bottom of the tube, the mass of fluid inside the tube, the inlet of fluid in the opening at the bottom of the tube and the walls of the tube. The next picture shows the assignation of group by different entities that the user is expected to find in the file available for downloading.

DEM 2 tutorial swimming groups.png

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

DEM 2 tutorial swimming DEM group.png

The FEM2DEM mesher was used to obtain this initial mesh of DEM spheres. See G-DEMPack Tutorial 3: DEM Meshers for a reference on the different meshers in the program. In this case, the chosen distribution of diameters for the elements is of 2mm with no variance.

DEM-FEM wall group

DEM 2 tutorial swimming DEM FEM group.png

The parameters in this section are identical to those in the G-DEMPack problem type, so no extra information is necessary in this case.

Inlet DEM group

DEM 2 tutorial swimming DEM inlet group.png

See G-DEMPack Tutorial 2: DemPack 2.0 for details. It is important to 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

DEM 2 tutorial swimming DEM Initial Conditions.png

This section is also identical to its counterpart in G-DEMPack, so no further explanations are needed.

Materials

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:

DEM 2 tutorial swimming materials section.png

The DEM part is identical to G-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-Fluid Interaction Settings

Most of the interaction parameters between the DEM spheres and fluid are inside the General Application Data section, whose overview is given next:

DEM 2 tutorial swimming general application data.png

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

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:

DEM 2 tutorial swimming fluid menu.png

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

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:

DEM 2 tutorial swimming Fluid Properties.png

In this particular case, the Water default material was assigned to the Property1, which is good enough in this sample simulation.

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:

DEM 2 tutorial swimming Elements Fluid.png

  • Important remarks
    • Make sure a property has been created before assigning the fluid element.

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:

DEM 2 tutorial swimming Elements Fluid Property.png

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

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:

DEM 2 tutorial swimming Initial Conditions.png

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

  • Important remarks
    • Make sure that the whole fluid boundary has some fluid condition applied. Each surface of the fluid external skin must be either Inlet, Outlet, Slip or No-slip.
    • Make sure that entities not belonging to the external skin are NOT selected when applying the fluid 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:

DEM 2 tutorial swimming inlet group.png

A vertical constant flow of 1m/s entering the bottom opening of the tube was chosen.

  • 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:

DEM 2 tutorial swimming No Slip.png

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.

  • Outlet pressure

Note that outlet pressure can be assigned to Points, Lines or Surfaces.

Choose which one you need before creating a new group. The user will create a new group named outlet and assign the upper circular surface to it. This surface represents the exit of the pipe. With the outlet created, it can be then assigned in the Outlet Pressure tab. The value of the pressure can be chosen. Typically 0.0.

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:

DEM 2 tutorial swimming mesh.png

On the other hand, the initial DEM spheres mesh should look like the following:

DEM 2 tutorial swimming mesh DEM detail.png

While the inlet surface mesh should be very similar to this:

DEM 2 tutorial swimming mesh DEM inlet detail.png

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:

DEM 2 tutorial swimming velocities1of4.png DEM 2 tutorial swimming velocities2of4.png DEM 2 tutorial swimming velocities3of4.png DEM 2 tutorial swimming velocities4of4.png

The next figure shows the stationary pressure field in the fluid:

DEM 2 tutorial swimming fluid pressure.png

The user can also make a cut in the mass of fluid and obtained a 2D view of the velocity field in the fluid:

DEM 2 tutorial swimming fluid velocities.png


Additional DEM Tutorials

Other tutorials can be found here.

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