Workshop 11 - Dem - Lbm 2os3z
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Workshop 11 – LBM-DEM Coupling
www.rocky-dem .com
OBJECTIVE
The purpose of this workshop is to present the 1-way coupling between DEM and Lattice-Boltzmann Method (LBM) to observe the particleinduced air flow. Covered Topics: Air Flow Vectors Plot
www.rocky-dem .com
2
PREREQUISITES
This workshop assumes that the is already familiar with Rocky interface and with the project workflow. If that is not the case, please refer to the Workshop 01 – Transfer Chute, for basic introduction about Rocky usage.
www.rocky-dem .com
3
HELP – MANUAL
For further information on any topic presented, we suggest searching the Manual, which provides in depth descriptions of the tools and parameters. To access it, click on Help, in the Toolbar, and select Manual, under Manuals options.
www.rocky-dem .com
4
HELP – MANUAL In the Manual, use the Search tab, to quickly find the topic you are looking for:
www.rocky-dem .com
5
GEOMETRY
The geometry in this tutorial is composed of: 1) Feed Conveyor 2) Surface
(1)
(2)
www.rocky-dem .com
6
PROJECT CREATION Open Rocky 4. Look for Rocky 4 in Program Menu or use desktop shortcut. Click on New Project, or in File, New Project (Ctrl+N).
New Project
Save Project
www.rocky-dem .com
7
PROJECT DETAILS The first step of the setup is to define any useful information of the project. Click on Study 01 and edit as shown.
www.rocky-dem .com
8
PHYSICS DEFINITION For this workshop, in order to reduce the simulation time, reduce the Numerical Softening Factor, in the Momentum tab.
www.rocky-dem .com
9
GEOMETRY IMPORT In Geometries, it’s possible either to create standard or import custom geometries. For this case the geometries will be imported in *.stl format. Right click on Geometries, select Import, Custom Geometry.
Select the following file: Surface
All parts will be imported using “mm” as Import Unit and keep the option Convert Y and Z Axes unchecked.
www.rocky-dem .com
10
FEED CONVEYOR DEFINITION
For this workshop, a Feed Conveyor will be created to input the material, without the need of an Inlet.
To do this, right-click on Geometries in the Data View, go to Create, and select Feed Conveyor. A new geometry part named Feed Conveyor <01> will be included in the tree; Change the parameters in each tab in order to define the Feed Conveyor according to the next slides.
www.rocky-dem .com
11
FEED CONVEYOR DEFINITION
Geometry:
Skirtboard:
Transition Length: 3 m
Material: Default Boundary
Loading length: 3 m
Width: 0.7 m
Belt width: 1 m
Length: 4.5 m
Triangle size: 0.1 m
Skirtboard height: 0 m
Belt Thickness: 0.025 m
Length offset: 1.5 m
Height offset: 0 m
Orientation: Alignment angle: 0º
Feeder Box:
Belt incline angle: 20º
Front plate offset: 0 m
Vertical Offset: 0.2 m
Drop box length: 1.8 m
Horizontal Offset: 0 m
Drop box width: 1.8 m
Out-of-plane offset: 0 m
Drop box height: 0.5 m
Return Belt Angle: 0º
Wall thickness: 0.025 m www.rocky-dem .com
12
FEED CONVEYOR DEFINITION
Head Pulley:
Belt motion:
Face width: 1.2 m
Belt speed: 3 m/s
Diameter: 0.5 m
Beginning start time: 0 s
Offset to Idlers: 0 m
Beginning stop time: 1000 s Acceleration period: 0 s
Belt profile:
Deceleration period: 0 s
Material: Default Belt Belt profile: Three rolls Use 0.371 ratio for Center Roll Length: Checked Troughing Angle: 35º Lower Corner Radius: 0.15 m
www.rocky-dem .com
13
MATERIAL DEFINITION In this workshop the three default materials will be used. Change Density for the Default Boundary and disable Use Bulk Density and the Density for Default Particles (as shown).
www.rocky-dem .com
14
INTERACTION BETWEEN MATERIALS To set the interaction properties, click on Material Interactions in the Data View.
From the left drop list, select Default Particles, and for the right drop list, select, in order: Default Boundary, Default Belt and Default Particle. Adjust the parameters for each combination according to the values shown on the next slide.
www.rocky-dem .com
15
INTERACTION BETWEEN MATERIALS
Default Particles
Static Friction: 0.6 Dynamic Friction: 0.6 Coefficient of Restitution: 0.1 Adhesive Distance: 0.0001 Force Fraction: 0
Default Belt
Static Friction: 0.3 Dynamic Friction: 0.3 Coefficient of Restitution: 0.1 Adhesive Distance: 0.0001 Force Fraction: 0
Default Boundary
Static Friction: 0.4 Dynamic Friction: 0.35 Coefficient of Restitution: 0.1 Adhesive Distance: 0.0001 Force Fraction: 0
Default Particles
www.rocky-dem .com
16
PARTICLE GROUP DEFINITION To create a new particle group, right click on Particles in the Data view and select the option Create Particles.
Doing this will generate a new Particle Group to set up.
www.rocky-dem .com
17
PARTICLE GROUP DEFINITION In the Geometry tab, define Enable Rotation, Shape Type, and Rolling Resistance (as shown).
In the Size Distribution tab the default values will be used (as shown). To visualize the new created particle, click on Particle <1> and click Preview. A new window will appear showing the particle geometry.
www.rocky-dem .com
18
MASS FLOW DEFINITION To create a new particle mass flow, right click Input in the Data view and select the option Create Particles Input.
Doing this will generate a new Particle Input to set up.
www.rocky-dem .com
19
MASS FLOW DEFINITION
Select Feed Conveyor <01> as the Entry Point, from the drop down list;
To add a new particle mass flow, click in the green plus button; Select the Particle Name from the drop down list and define the Tonnage (as shown).
www.rocky-dem .com
20
AIR FLOW DEFINITION To create a Air Flow setup, click on CFD Coupling in the Data view. In the Data Editors, the Coupling Mode can be selected from the drop down list. Select the Air Flow option.
Doing this will generate a new Air Flow CFD Coupling to set up in the Data view. The available options are described in the next slide.
www.rocky-dem .com
21
AIR FLOW DEFINITION Operation Properties Use Air Flow: Enables/Disable Rocky Air Flow calculations Start When Particle Enter: Enables Rocky Air Flow calculations to start as soon as particles enters the Air Flow box domain.
Air Properties Air Density: The density of the air. Air Viscosity: The viscosity of the air.
Lattice-Boltzmann Details Cell Size: The size of the Air Flow cell. Interaction Scale: Determines the interaction between the Particle and the air. Start Time: When Start When Particles Enter is cleared, this is the time that Air Flow calculations begin during the simulation. Speed of Sound: The speed of sound, which is used to calculate Air Flow . * For more information on how Rocky calculates boundary conditions, see the 2000 paper by Verberg and Ladd entitled, "Lattice-Boltzmann Model with Sub-Grid-Scale Boundary Conditions."
Boundary Conditions: Method applied for the calculations, affecting accuracy and stability.* Coordinate Limits: Fluid Domain limits. www.rocky-dem .com
22
AIR FLOW DEFINITION In the Air Flow tab define the Cell Size, Interaction Scale and Coordinate Limits (these can be different than the DEM domain limits), as shown. Interaction Scale was modified from default value (0.25) only for workshop purposes. For general analysis, the default value is recommended.
Set mesh size
Set fluid domain limits www.rocky-dem .com
23
SOLVER DEFINITION In the Time Configuration tab use the default settings(as shown)
In the General Settings tab, uncheck the Use Compressed Files and select either U or GPU as Simulation Target, and then the Number of Processors or Target GPU and unselect Use Compressed Files. For this workshop, U will tend to solve fastest due the low particle count. Click Start Simulation!
www.rocky-dem .com
24
SIMULATION
Particle states can be viewed in real time as the simulation progresses.
The speed of the simulation depends on various factors such as: Number of mesh elements used to define the geometry Number of s in the simulation domain at any time Smallest particle size and material stiffness The particle shape and the number of vertices used to define the shape
Frequency of file output
www.rocky-dem .com
25
POST PROCESS – 3D VIEW Select an appropriate Time and Property for the particles to investigate the results.
www.rocky-dem .com
26
POST PROCESS – AIR FLOW In the Coloring tab of Air Flow, check Visible and Vectors and select Velocity from the Property drop down list (as shown).
www.rocky-dem .com
27
PROCESS – PLANE
Create a Plane crossing the Air Flow to plot the fluid Properties. To create it, right click Air Flow and select Plane, under Process.
Use the values shown for Plane Origin and Normal, in the Plane tab. To finish, drag and drop the Absolute Velocity, from the Properties tab, on the 3D View to display the velocity contours.
www.rocky-dem .com
28
PROCESS – PLANE
www.rocky-dem .com
29
PROCESS – PROPERTY
Create a Property subset of the Air Flow to show regions with air absolute velocity higher than a certain value. To create it, right click on Air Flow and select Property, under Process. Use the values shown for Property, Mode, Type and Range, in the Property tab. To finish, drag and drop the Absolute Velocity, from the Properties tab, on the 3D View to display the velocity contours.
www.rocky-dem .com
30
PROCESS – PROPERTY
Region with air velocity higher than 0.5 m/s
www.rocky-dem .com
31
CONCLUSIONS
Rocky was used to simulate the induced streams due to the particle movement. During this workshop, it was possible to: understand the basics of the Rocky interface import sample geometries
create basic geometry in Rocky define basic Lattice-Boltzmann parameters post-process the Lattice-Boltzmann Air Flow
www.rocky-dem .com
32
www.rocky-dem .com
OBJECTIVE
The purpose of this workshop is to present the 1-way coupling between DEM and Lattice-Boltzmann Method (LBM) to observe the particleinduced air flow. Covered Topics: Air Flow Vectors Plot
www.rocky-dem .com
2
PREREQUISITES
This workshop assumes that the is already familiar with Rocky interface and with the project workflow. If that is not the case, please refer to the Workshop 01 – Transfer Chute, for basic introduction about Rocky usage.
www.rocky-dem .com
3
HELP – MANUAL
For further information on any topic presented, we suggest searching the Manual, which provides in depth descriptions of the tools and parameters. To access it, click on Help, in the Toolbar, and select Manual, under Manuals options.
www.rocky-dem .com
4
HELP – MANUAL In the Manual, use the Search tab, to quickly find the topic you are looking for:
www.rocky-dem .com
5
GEOMETRY
The geometry in this tutorial is composed of: 1) Feed Conveyor 2) Surface
(1)
(2)
www.rocky-dem .com
6
PROJECT CREATION Open Rocky 4. Look for Rocky 4 in Program Menu or use desktop shortcut. Click on New Project, or in File, New Project (Ctrl+N).
New Project
Save Project
www.rocky-dem .com
7
PROJECT DETAILS The first step of the setup is to define any useful information of the project. Click on Study 01 and edit as shown.
www.rocky-dem .com
8
PHYSICS DEFINITION For this workshop, in order to reduce the simulation time, reduce the Numerical Softening Factor, in the Momentum tab.
www.rocky-dem .com
9
GEOMETRY IMPORT In Geometries, it’s possible either to create standard or import custom geometries. For this case the geometries will be imported in *.stl format. Right click on Geometries, select Import, Custom Geometry.
Select the following file: Surface
All parts will be imported using “mm” as Import Unit and keep the option Convert Y and Z Axes unchecked.
www.rocky-dem .com
10
FEED CONVEYOR DEFINITION
For this workshop, a Feed Conveyor will be created to input the material, without the need of an Inlet.
To do this, right-click on Geometries in the Data View, go to Create, and select Feed Conveyor. A new geometry part named Feed Conveyor <01> will be included in the tree; Change the parameters in each tab in order to define the Feed Conveyor according to the next slides.
www.rocky-dem .com
11
FEED CONVEYOR DEFINITION
Geometry:
Skirtboard:
Transition Length: 3 m
Material: Default Boundary
Loading length: 3 m
Width: 0.7 m
Belt width: 1 m
Length: 4.5 m
Triangle size: 0.1 m
Skirtboard height: 0 m
Belt Thickness: 0.025 m
Length offset: 1.5 m
Height offset: 0 m
Orientation: Alignment angle: 0º
Feeder Box:
Belt incline angle: 20º
Front plate offset: 0 m
Vertical Offset: 0.2 m
Drop box length: 1.8 m
Horizontal Offset: 0 m
Drop box width: 1.8 m
Out-of-plane offset: 0 m
Drop box height: 0.5 m
Return Belt Angle: 0º
Wall thickness: 0.025 m www.rocky-dem .com
12
FEED CONVEYOR DEFINITION
Head Pulley:
Belt motion:
Face width: 1.2 m
Belt speed: 3 m/s
Diameter: 0.5 m
Beginning start time: 0 s
Offset to Idlers: 0 m
Beginning stop time: 1000 s Acceleration period: 0 s
Belt profile:
Deceleration period: 0 s
Material: Default Belt Belt profile: Three rolls Use 0.371 ratio for Center Roll Length: Checked Troughing Angle: 35º Lower Corner Radius: 0.15 m
www.rocky-dem .com
13
MATERIAL DEFINITION In this workshop the three default materials will be used. Change Density for the Default Boundary and disable Use Bulk Density and the Density for Default Particles (as shown).
www.rocky-dem .com
14
INTERACTION BETWEEN MATERIALS To set the interaction properties, click on Material Interactions in the Data View.
From the left drop list, select Default Particles, and for the right drop list, select, in order: Default Boundary, Default Belt and Default Particle. Adjust the parameters for each combination according to the values shown on the next slide.
www.rocky-dem .com
15
INTERACTION BETWEEN MATERIALS
Default Particles
Static Friction: 0.6 Dynamic Friction: 0.6 Coefficient of Restitution: 0.1 Adhesive Distance: 0.0001 Force Fraction: 0
Default Belt
Static Friction: 0.3 Dynamic Friction: 0.3 Coefficient of Restitution: 0.1 Adhesive Distance: 0.0001 Force Fraction: 0
Default Boundary
Static Friction: 0.4 Dynamic Friction: 0.35 Coefficient of Restitution: 0.1 Adhesive Distance: 0.0001 Force Fraction: 0
Default Particles
www.rocky-dem .com
16
PARTICLE GROUP DEFINITION To create a new particle group, right click on Particles in the Data view and select the option Create Particles.
Doing this will generate a new Particle Group to set up.
www.rocky-dem .com
17
PARTICLE GROUP DEFINITION In the Geometry tab, define Enable Rotation, Shape Type, and Rolling Resistance (as shown).
In the Size Distribution tab the default values will be used (as shown). To visualize the new created particle, click on Particle <1> and click Preview. A new window will appear showing the particle geometry.
www.rocky-dem .com
18
MASS FLOW DEFINITION To create a new particle mass flow, right click Input in the Data view and select the option Create Particles Input.
Doing this will generate a new Particle Input to set up.
www.rocky-dem .com
19
MASS FLOW DEFINITION
Select Feed Conveyor <01> as the Entry Point, from the drop down list;
To add a new particle mass flow, click in the green plus button; Select the Particle Name from the drop down list and define the Tonnage (as shown).
www.rocky-dem .com
20
AIR FLOW DEFINITION To create a Air Flow setup, click on CFD Coupling in the Data view. In the Data Editors, the Coupling Mode can be selected from the drop down list. Select the Air Flow option.
Doing this will generate a new Air Flow CFD Coupling to set up in the Data view. The available options are described in the next slide.
www.rocky-dem .com
21
AIR FLOW DEFINITION Operation Properties Use Air Flow: Enables/Disable Rocky Air Flow calculations Start When Particle Enter: Enables Rocky Air Flow calculations to start as soon as particles enters the Air Flow box domain.
Air Properties Air Density: The density of the air. Air Viscosity: The viscosity of the air.
Lattice-Boltzmann Details Cell Size: The size of the Air Flow cell. Interaction Scale: Determines the interaction between the Particle and the air. Start Time: When Start When Particles Enter is cleared, this is the time that Air Flow calculations begin during the simulation. Speed of Sound: The speed of sound, which is used to calculate Air Flow . * For more information on how Rocky calculates boundary conditions, see the 2000 paper by Verberg and Ladd entitled, "Lattice-Boltzmann Model with Sub-Grid-Scale Boundary Conditions."
Boundary Conditions: Method applied for the calculations, affecting accuracy and stability.* Coordinate Limits: Fluid Domain limits. www.rocky-dem .com
22
AIR FLOW DEFINITION In the Air Flow tab define the Cell Size, Interaction Scale and Coordinate Limits (these can be different than the DEM domain limits), as shown. Interaction Scale was modified from default value (0.25) only for workshop purposes. For general analysis, the default value is recommended.
Set mesh size
Set fluid domain limits www.rocky-dem .com
23
SOLVER DEFINITION In the Time Configuration tab use the default settings(as shown)
In the General Settings tab, uncheck the Use Compressed Files and select either U or GPU as Simulation Target, and then the Number of Processors or Target GPU and unselect Use Compressed Files. For this workshop, U will tend to solve fastest due the low particle count. Click Start Simulation!
www.rocky-dem .com
24
SIMULATION
Particle states can be viewed in real time as the simulation progresses.
The speed of the simulation depends on various factors such as: Number of mesh elements used to define the geometry Number of s in the simulation domain at any time Smallest particle size and material stiffness The particle shape and the number of vertices used to define the shape
Frequency of file output
www.rocky-dem .com
25
POST PROCESS – 3D VIEW Select an appropriate Time and Property for the particles to investigate the results.
www.rocky-dem .com
26
POST PROCESS – AIR FLOW In the Coloring tab of Air Flow, check Visible and Vectors and select Velocity from the Property drop down list (as shown).
www.rocky-dem .com
27
PROCESS – PLANE
Create a Plane crossing the Air Flow to plot the fluid Properties. To create it, right click Air Flow and select Plane, under Process.
Use the values shown for Plane Origin and Normal, in the Plane tab. To finish, drag and drop the Absolute Velocity, from the Properties tab, on the 3D View to display the velocity contours.
www.rocky-dem .com
28
PROCESS – PLANE
www.rocky-dem .com
29
PROCESS – PROPERTY
Create a Property subset of the Air Flow to show regions with air absolute velocity higher than a certain value. To create it, right click on Air Flow and select Property, under Process. Use the values shown for Property, Mode, Type and Range, in the Property tab. To finish, drag and drop the Absolute Velocity, from the Properties tab, on the 3D View to display the velocity contours.
www.rocky-dem .com
30
PROCESS – PROPERTY
Region with air velocity higher than 0.5 m/s
www.rocky-dem .com
31
CONCLUSIONS
Rocky was used to simulate the induced streams due to the particle movement. During this workshop, it was possible to: understand the basics of the Rocky interface import sample geometries
create basic geometry in Rocky define basic Lattice-Boltzmann parameters post-process the Lattice-Boltzmann Air Flow
www.rocky-dem .com
32
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