'Ring with Pressure from CSV file' simulation project by rszoeke


#1

I created a new simulation project called 'Ring with Pressure from CSV file':

Copy of the project Ring_with_Pressure - creat a ring with a pressure taken from a txt.File or csv.File by @lkr


More of my public projects can be found here.


#2

Hello rszoeke,

could you please explain the driving rules of the load distribution using tabular data and interpolation? It is not realy clear for me based on your model.
Thanks in advance!

Bests,
Csaba


#3

Hello @potyka_csaba,
let me try to explain this, as I have to admit our help on this is not ideal.

Let’s start with the initial task:

  • inner pressure in the tube due to some internal flow
  • the pressure distribution was measured experimentally or computed with some CFD analysis and results in a several data points, plotted they look like this:

Now let’s go through the settings step-by-step:

  1. Applying this as a pressure load in SimScale leaves us with two different options:
    -> Using an analytical formula to define the pressure load (this would require fitting the data to some analytical formula, probably a polynomial)
    -> Defining a function by using the table data as input and defining some interpolation and extrapolation properties
    If either of those options is chosen, the initial scalar value (now grayed-out) does not matter any more. It is ignored.

  2. Now we need to define which should be the independent parameter of the function. In our case it is the Z-Coordinate. For the solid mechanics analysis types we currently can only have one independent parameter, for fluid mechanics there can be multiple active parameters.

  3. We upload the file and can visually check if its contents are interpreted correctly by selecting show:

  4. We select in which column of the CSV-file the independent parameter values are listed (index starts at 1)

  5. We select in which column of the CSV-file the dependent data values are listed (index starts at 1)

  6. To allow the solver to evaluate the given data also at points that are not directly given, we have to define the interpolation rule. In most cases linear is the best choice, but also logarithmic would be possible.

  7. If values outside of the parameter range as defined by the CSV-file would be requested, extrapolation rules must be specified. The correct choice depends on the application.

Generally, if a value depends on the coordinates (X,Y or Z) the following has to be considered:

  • all coordinates refer to the initial mesh coordinates (undeformed state) and not to the coordinates in the deformed state.
  • for evaluation of loads that are applied to elements (pressure, distributed force, volumetric load) the value for each element is evaluated at the center of the element. For loads/constraints that are applied to nodes, the functions are evaluated at the locations of those nodes.

I hope this answers your questions. If not, let me know and we can go into the details.

Best,
Richard


#4

Hello @rszoeke!

Thanks for the explanation! I think it is detailed enough :+1:. I will try it soon!

Bests,
Csaba