Friday, November 14, 2014

Rosetta Orbiter in Wake of Comet 67P

AG/CFD (Actual Geometry) Analysis performed by Stallion 3D with HIST for #SimulationFriday.

Stallion 3D took just seconds (with no need for pre-processing) to automatically import, grid and begin the compressible Navier-Stokes analysis of the water vapor, ice particles and dust streaming past the Rosetta orbiter in the wake of Comet 67-P’s.

Close up of the orbiter geometry in Stallion 3D.  


Analysis for the arbitrary geometries was performed on a on an HP Pavillion Laptop (Quad-Core) for a total of 4 hours.
Streamline of the flow past the Rosetta Orbiter

Rosetta image Credit:


More information can be found at http://www.hanleyinnovations.com.

Thanks for reading.

Thursday, September 25, 2014

Stallion 3D Lift/Drag Study

Stallion 3D is a modern  aerodynamics and computational fluid dynamics (CFD) analysis software tool.  The software allows users to bypass the time-consuming grid generation step and setup their problem for analysis in just a matter of a few seconds.  Stallion 3D is the best tool for aerodynamics analysis of arbitrary geometries on your MS Windows PC.

The following pictures are results obtain using Stallion 3D for  a lift and drag study of the DLR F4 wing-body.    The geometry was obtained from NASA OpenVsp hangar. Extensive data for this study was obtained from NASA 1st Drag Prediction Workshop (DPW1).  The url is: http://aaac.larc.nasa.gov/tsab/cfdlarc/aiaa-dpw/Workshop1/workshop1.html.

Only 500,000 computation cells were used for the present Stallion 3D analysis.  Results were obtained after 4 hours of computation time for each angle of attack using a laptop computer under MS Windows.  To speed-up the simulations, two cases were run simultaneously on the laptop.  This allowed a complete study in less than 24 hours.

Stallion 3D pressure distribution for DLR F4 at 2 deg angle of attack


CL versus angle of attack.  Results are from Stallion 3D
and CFL3D (as reported during DPW1).


Lift vs. Drag for the DLR F4 wing body.  Since the 
Euler equations was used for Stallion 3D, the graph shows 
pressure drag (CD_pres) for Stallion 3D.  This is compared
against the total drag from CFL3D and the experiments.


Pressure coefficient a station along the wing at 2 deg angle of attack.
The lines are for results obtained  by CFD3D as presented at DPW1.

More information about Stallion 3D can be obtained from http://www.hanleyinnovations.com/stallion3d.html

Thanks for reading.  Do not hesitate to telephone us at (352) 240-3658 or email at hanley@hanleyinnovations.com if you have any questions.

Friday, September 19, 2014

Five Benefits of Interactive Airplane Design

Its amazing how quickly a designer can compose a working airplane with 3DFoil, our interactive analysis and design tool.  The following video shows how airfoils and 3D planform shapes work together to size & determine stability of a new designs.



Since interactive is a word that is often used to describe computer programs, I would like to list 5 benefits that 3DFoil brings to interactive aircraft and hydrofoil design.

Benefit 1:  The airfoils are all built into the program.  Unlike other CAD software, you do not have to browse the web to find airfoil shapes for your new designs.

Benefit 2:  You can analyze the airfoils on the fly.  You can test and compare candidate airfoils in a matter of second using the built-in airfoil analysis tool.  Compare  Cl, Cd, moments and the angle for maximum lift of your airfoil shapes.

Benefit 3: Interactive means using the airfoils in 3D wing planform shapes and immediately getting the lift, drag (vortex and profile) and moments.  As shown in the video, this only take a few seconds.

Benefit 4: An airplane is like a bicycle (the Wright brothers built bicycles).  It must support a payload and it should be properly balanced in flight.  This means interactively determining both the longitudinal and lateral stability derivatives to ensure the performance of your design.

Design and analysis of kite-surfacing canopy.

Benefit 5: 3DFoil interactive means that you will have something concrete to show for your efforts. The software can export both .dxf files of the airfoils and a 3D .STL file of the surfaces.  You can use these for 3D-printing a fully working prototype for wind tunnel testing.

More information about 3DFoil can be found at http://www.hanleyinnovations.com/3dfoil.html

Thanks for reading.  Do not hesitate to contact us at (352) 240-3658 for more information.

Wednesday, September 17, 2014

Aerodynamics of a Hand Launched UAV

The business for small hand launched UAVs can be quite lucrative.  Make no mistake, however, theses aircraft are not high-priced model (toy) airplanes that you can just sell to the government.  UAVs that are highly coveted for surveillance work by private and government organizations must be extremely durable (tough), all weather and have the range and endurance to fulfill their mission. They must also be quiet.

3D Analysis using Stallion 3D.  Colors show surface pressure.

The above specifications presents a myriad of conflicting design requirements that must be successfully navigated by the UAV aerodynamics engineer.  The aerodynamics software by Hanley Innovations is the only suite of programs that equips the designer with a set of tools to complete their tasks in a timely manner.  For example, Stallion 3D, a full-fledged aerodynamics software package, requires no user grid generation.  The workflow to setup a simulation takes seconds and the software runs on an ordinary PC or laptop computer under the familiar MS Windows environment.  The following video shows the process.


Video shows how to efficiently analyze a UAV using Stallion 3D

Requirements for a successful UAV design include:
1. Airfoils with good lift/drag ratio and soft stall characteristics
2. A wing/body (fuselage) combination that provides high lift and low induced drag.
3.  Good longitudinal stability characteristics (marginally stable UAVs are difficult to fly and gets damaged during landing and takeoff).
4. Good lateral stability characteristics and damping derivatives.

More information about our suite of software can be found a http://www.hanleyinnovations.com.  You may also call us at (352) 240-3658.

Thanks for reading.

P.S. Our airfoil analysis software starts at only $29 (they predict  the angle of attack for maximum lift and separation). More information can be found at: http://www.hanleyinnovations.com/vf50.html

Wednesday, September 3, 2014

5 Tedious CFD Chores You Can Skip with HanleyCFD

The hallmark of any process innovation is the elimination of a significant step (or number of steps) from the workflow and yet maintain (or improve) the high standards of the final product.  Hanley Innovations CFD products (HanleyCFD) remove the grid generation step from your workflow during the computational fluid dynamics, CFD, analysis of your product.  This speeds up the design process and gives you an advantage over the competition.

Since saying automated gridding is a honor that all software can boast (we are using a computer for CFD after all), here are 5 tasks and worries  you can definitely leave behind when you analyze your designs using HanleyCFD.



1.  Grid Quality Worries
There is no need for worrying about grid quality.  Every single cell in a HanleyCFD grid is Cartesian, i.e.a rectangular hexahedron (my old notes from 18.335 say that these are the best grids for CFD). Furthermore, there is no overhead in transforming the 3-D Navier-Stokes and Euler equations to conform to a surface fitted grid.  You can solve them the way nature intended (in Cartesian form).


Comparison of Cartesian Euler Solver & Potential Flow in MultiElement Airfoils 5.

2. Small Features Can Stay
A small nick, scratch or bump on a CAD surface mesh can send an extrusion based grid generation process awry.  It is the painful equivalent of bare footing a tack (or Lego piece) on an otherwise smooth floor.  With HanleyCFD, there is no need for a time consuming cleanup of the CAD surface. Small features can stay and save you time in the analysis work flow.

3. Dealing with Small Acute Angles & Paper Thin Surfaces in the Geometry
You can just ignore these cute little triangles with HanleyCFD.  CFD based on tetrahedral grids can have accuracy problems if they encounter these features.  Increasing the mesh resolution can often exacerbate the problem and lead the solver down an endless inverted oblivion. The following  video shows how Stallion 3D,  the HanleyCFD flagship, deals with a geometry mired in small acute angles.

Watch this video to see the workflow from analyzing difficult geometries.


4.  The Debate Over Important Geometry Features
HanleyCFD helps you to avoid the long debate (with yourself or team members) whether or not a geometry feature is important to the analysis and the physics of the flow.  Keeping a feature translates to more time performing the mesh generation. By removing the feature, you can miss an important physical result.  HanleyCFD will analyze the feature without the extra time spent for mesh generation.

5.  Modification of the Geometry That's in your Mind
Too often, you are forced to modify your design to appease cost and time constraints of the analysis workflow.  With HanleyCFD, you have no problems analyzing the concepts that can change the world.

Stallion 3D analysis of Wright Flyer (TurboSquid model).

HanleyCFD and Stallion 3D can be purchased at http://www.hanleyinnovations.com.  Please call us at (352) 240-3658 for more information.

Thanks for reading.

Tuesday, August 5, 2014

Onera M6 Wing Revisited

Stallion 3D uses an automatic Cartesian grid to provide the best accuracy and computational efficiency when compared to the topology of other grids.  The grid is automatically generation and the process is invisible to the user during the workflow.

Stallion 3D offers users the option to create simulation sizes ranging form quick (about 60,000 cells) to detailed (about 2,00,000 cells).   The Quick run allows users to preview how well a geometry performs before committing to a larger flow model size.  The results below were obtain from two different simulation sizes.  The first one is about 440,000 cells and is referred to as the coarse grid in the graphs.  The second model is about 1,600,000 cells and is referred to the fine grid.

A drop down box allows user to select the size of the simulation.

Stallion 3D accepts 3D solid models in the .stl format.  The stl file reader allows users to scale, rotate and position the model in the flow field.  The stl file of the Onera M6 wing  for this example is obtained from NASA OpenVSP.

The simulation parameters are setup with the well know case of M=0.84 and an angle of attack of 3.06 degrees.  The result below shows the pressure on the surface of the wing for the fine grid case.

Analysis of Onera M6 Wing. V=288 m/s. Angle of Attack = 3.06 degrees


Cp at the 20% span location. 

Cp at the 44% span location.


Cp at the 65% span location.


Cp at the 90% span location.

Cp at th 95% span location.

Stallion 3D compute forces and coefficients by integrating the pressure at the surface.  This often provides good results for the lift and pressure drag.  Caution must be taken when using this option if the model consists of a small number of facets or the geometry has a significant number of inwardly facing facets normal.

Stallion 3D Forces integrated on the geometry (Facets)
    
No. Cells
          CL          CD (Pressure)
Coarse Grid
440,000
0.268
0.0178
Fine Grid
1,600,000
0.275
0.0155
CFL 3D**
N/A
0.266
0.0172 (total)
Results Table for Faceted Surface Force Integration.

Another option for finding the forces (especially when the geometry is questionable) is to use the Cartesian front option.  This is a boundary consisting of the outward faces of the Cartesian cells closest to the geometry.  To find the forces, the momentum equation is evaluated on the cell faces (Cartesian Front).  This method provides good results for fine grids.  In any case, the results for both methods of force integration should agree with each other.

Forces integrated on the Cartesian Front (Momentum Equation)
    
No. Cells
          CL        
CD (Pressure)
Coarse Grid
440,000
0.273
0.0124
Fine Grid
1,600,000
0.278
0.0112
CFL 3D**
N/A
0.266
0.0172 (total)
Results Table for Cartesian Front Force Integration

More information about Stallion 3D can be found at http://www.hanleyinnovations.com

Related Article:
Onera M6 Wing, Star of CFD, http://www.onera.fr/en/actualites/image-du-mois/onera-m6-wing-star-cfd

 CFL 3D Viscous Calculations: http://cfl3d.larc.nasa.gov/Cfl3dv6/cfl3dv6_testcases.html#onera **

Do not hesitate to email or telephone us at (352) 240-3658 if you have any questions.
Thanks for reading.

Saturday, July 26, 2014

Stepping Up Your Aerodynamics Conceptual Analysis

At Hanley Innovations, we develop software tools that enables you to easily transform your ideas into actual flying prototypes.  One way to get your idea to work is to start with a concept about which you are quite certain, I mean really, really confident (an airfoil, for example), and then, like the Science Channel suggest, you Build It Bigger.

VisualFoil Enables You to Clarify Airfoil Concepts Before
Moving On to the Next Step. Airfoil Analysis Starts at $29

With a family of airfoils in hand (because no one can fly in 2-dimensions), the concept steps up to a wing (because birds have them and .... they can fly very well).  The next simple step is to extrude your airfoil (s) into a 3-D surface to support your weight at various flight speeds.  What is soon realized is that other surfaces of various shapes, sizes & orientation (which use your original airfoil concepts) are need to help balance your design in flight (stability). Stability depends in part on weight distribution (center of gravity) over the entire (what we can now call) airplane with respect to the neutral point (similar to aerodynamic center) location.

3DFoil Can Be Used to Design  Multiple Wings
and Workout Weight and Stability Issues.

For most people, trial by 3DFoil, results in concepts which you print, template and fly.  But what if, just what if you still want to Build it Even Bigger.  Stallion 3D can be used to take concepts even further.  The program can actually read-in your project files from 3DFoil and further the analysis of your concept. The video shows how Stallion 3d imports and analyzes a kite that was created in 3DFoil or MultiSurface Aerodynamics.

Stallion 3D will Read-In MultiSurface Aero/3DFoil Files for Detailed 3D Analysis

The next time your have a BIG idea, do not hesitate to visit Hanley Innovations to Build It Even Bigger.


The Aerodynamics Class Pack combines airfoil, wing and the Stallion 3D software and the modules can be accessed your entire class on their individual PC over the course of one year.

You may also call us at (352) 240-3658.

Thanks for reading.