This tutorial shows how to examine the aerodynamic characteristics of the NACA2412 airfoil, calculating lift, drag, and moment coefficients at various angles of attack for a comprehensive understanding of its performance.
Flow Simulation Set Up
Dimensions
- Chord length =1.5 m,
- Span = 1 m
Analysis Type
Incompressible steady-state analysis.
Turbulence Model
k-Omega SST
Fluid : Air
Initial Conditions
- (š) Kinematic viscosity = 1.33e-5 š2/s
- Density = 1.2933 kg/m3
- Incoming Flow Velocity = 80 m/s
Let’s now delve into the SimScale process one step at a time for this particular problem.
Just a heads-up: The ideal way to begin is by creating a ‘New Project’ and then importing the CAD model. However, we’ve already taken care of the steps for you, including importing the CAD model. You can get started right away with the ‘Creation of Flow Domain‘ step.
Prepare the CAD Model and Select the Analysis Type
Open a ‘New Project’ & import the CAD model
- Click open the new project, and fill the details as following dialogue box appears.
- Once details are entered, Click ‘Create Project‘.
- Click + next to GEOMETRIES, and import the CAD model
Creation of Flow Domain
- Once imported, click the geometry, and click ‘Edit with CAD mode‘.
- In the CAD mode, select CREATE > External, and enter the following dimensions, for creating the external flow volume. It will get saved as the ‘Flow Region’.
- Once the external flow volume has been created, Select DELETE from theoptions under BODY, and choose the geometry as the volume, and press APPLY.
Create Simulation
- Select ‘Incompressible’ and click Create Simulation
- Once the Simulation has been created, you can rename it and edit the characteristics as shown here.
Assigning the Material and Boundary Conditions
Define a Material
- Select āAirā by clicking ā+ā next to āMaterialā.
- Edit the values of the default coefficients to the set values as given in the image.
Define the Initial Conditions
- Set the Initial Conditions, namely
- (P) Gauge static pressure = 0 Pa
- (U) Velocity(Global) = 0 m/s
- (k) Turb Kinetic Energy = 3.84e-3 mĀ²/sĀ²
- (w) Specific Dissipation Rate = 88.53 1/s
Define Boundary Conditions
- To set up the ‘Boundary Conditions’, enter the values as given in the snippets.
- Set the āInlet-Outletā boundary condition for the top and bottom faces of the flow region.
- To set the boundary condition for Outlet to be āPressure Outletā.
- To set the symmetry for 2D geometry, select Symmetry
- To set the boundary condition for āWallā by selecting all the faces of the airfoil.
- To set the boundary condition for Velocity Inlet.
To assign velocity component values for each Angle of Attack, input the corresponding values from the provided table for each angle of attack.
Numerics and Simulation Control
- Set the āNumericsā and ‘Simulation Control’ as given in the āFINISHED PROJECTā.
- NOTE: In this section, there are variations in the input values for different angles of attack to achieve the most accurate results, considering the respective flow variations. Therefore, please adhere to the values provided in the final project.
Result Control
Below āResult Controlā, click ā+ā next to ‘Force and Moment Coefficients’.
- Select all the faces of the airfoil.
- Now, let’s establish the ‘Force and Moment Coefficients’ by clicking on the ‘+‘ icon and entering the specified values.
- Just like the velocity components, to allocate the component values of lift and drag for each Angle of Attack, input the corresponding values from the provided table for each angle of attack.
Mesh Generation
- Click on Mesh, and make changes to the Mesh Settings.
- Following the above, Click Generate to generate Mesh, and wait for the mesh to get generated.
NOTE: Check the Event Log below the dialogue box once the mesh is generated to check for the mesh quality before proceeding. If the mesh is not correctly generated, Simulation Run in the next stage can get terminated prematurely.
Simulation
To initiate the simulation, follow these steps:
- Expand the ‘Simulation Runs’ section by clicking on the ‘+‘ symbol.
- Then, select the ‘Run’ option to start the simulation process, and then click ‘Start’.
This action will prompt the software to execute the simulation based on the defined parameters and settings.
Processing
- Select the āConvergence plotsā below āRunā to check for convergence. In an iterative method, residuals represent the disparities in the solution. Achieving numerical precision involves minimizing these residuals.
- Typically, aiming for residuals below 1e-3 is a suitable threshold to proceed to the next assessment.
- Another aspect to consider is examining the exact values for Force coefficients, such as the coefficient of drag, lift, moment, and so forth, to ascertain their convergence.
This entails analyzing whether these coefficients have stabilized and reached consistent values over successive iterations, indicating convergence in the solution.
Post- Processing
- Once the simulation is āCompleteā, you can access the post-processing environment by clicking on āSolution Fieldsā or āPost-process resultsā.
After checking the residuals, if you think it has not yet been converged, you will see the āContinue to run >>ā icon, in which you can enter the end time to be your present end time and increase the maximum run time.
If not, continue by selecting ‘Post-process results.’ See below for all available post-processing options in SimScale:
- Cut Plane: Slice the domain to visualize parameters on the plane.
- Vectors: Plot vector fields to represent quantities like velocity or force.
- Contour Plot: Display scalar field data using contour lines.
- Probe Points: Insert points to extract data at specific locations.
- Particle Trace: Generate streamlines from seed faces to observe flow patterns.
- Iso Surface: Highlight regions with specific scalar values.
- Iso Volume: Highlight regions within a defined scalar value range.
- Rotational View: Inspect rotational regions by creating blade-to-blade views.
- Animation: Create animations of simulation results.
- Field Calculator: Generate new fields using predefined functions and operators.
- Compare: Visualize result fields from two different simulations side by side.
Please refer to the accompanying image to explore the full range of available options for post-processing. These options provide diverse tools for analyzing and visualizing simulation results in SimScale.
Repeat
Follow the steps outlined above for each angle of attack, while adjusting the velocity, lift, drag components, and relevant numerical parameters as specified in the tables provided. For a clearer understanding, you can refer to the completed project.
