Learning Forum

[KumarVaibhav]

I needed to know i have a metal sheet in the form of a leaf to be attached on a pole.The structure is just like a leaves coming out from a tree.I needed to decide what material be useful to face the wind loads on this leaf?Will the SS 316L or the Magnesium alloy would better face the wind loads.The leaf is 2m long and 1 m wide.Kindly tell how can ansys be used for this case.It would be appreciated if the physics is explained by someone?Find the file geometry

[Rob]

The starting point will be to run a CFD calculation to determine the wind load: this may be difficult to do accurately within the cell count limits of the Student bundle. 

From there you can transfer the pressure (or force) over to Mechanical and check the deflection. Try this with different materials until you have achieve the level of deflection you're happy with. 

The ANSYS software is used to verify/validate/optimise an existing design. So, you create the starting point and then use the tools to confirm it works or improve the performance. Within ANSYS Fluent there are also optimiser tools capable of altering the design to reach a preset goal: within Workbench the design of experiment tools combine with parameters & optimiser technology to do the same for Mechanical. 

[KumarVaibhav]

oh thanks woolhow!

[peteroznewman]

Kumar attached a very thin-walled (1.2 mm), solid model, STEP file to the post above. In a previous discussion, he asked for help meshing that in Mechanical. I provided a midsurface model of that geometry that meshed very easily in Mechanical.  I write this so someone doesn't spend time trying to extract the midsurface from this STEP file.

I'm a CFD novice and I am curious to read whether using 3D surface models for a body in an airflow is a good starting point for this analysis.

[KumarVaibhav]

yes you did but let me know the body operations how did you perform on the geometry or rather which part of geometry?pls share the wbpz file for 16 version

[peteroznewman]

A version 15 wbpz file for a midsurface version of the leaf is attached to this post.

The body operations to go from the solid model to the midsurface model are described in this post.

[Rob]

If you take a thin surface into ANSYS Fluent it'll be turned into a wall & wall:shadow, so we can track the pressure on each side of it. The difficulty can be getting the meshing tool to see the surface so it's common to create a volume/split to avoid having hanging faces. 

[KumarVaibhav]

I did a preliminary analysis of wind load over a cube using coupled fsi in fluent and then structural.I am confused which direction of force should i take in CFD results i.e force in x,y or z.I want to know which force direction is more in my case.Can somebody see the zip file attached and tell me the way to view the force in kgf at the faces from one end to another  horizontally,vertically and diagonally.The cube is at a height of 40 metres ,will it affect the wind load which i think does  but in what proportions.Also it shows negative pressure values,what do they mean?Any CFD expert pls review it

[Rob]

As ANSYS staff we're unable to review any case/project files. If you can share the Workbench project archive someone in the community may be able to help. 

Re the forces, you need to decide which direction you want to see the data for (look in Reports -> Forces). 

Re the pressure, assuming you're looking at static pressure, this is relative to gauge. Please look up the Operating Pressure definitions in the Documentation.