Tables are one possibility, besides formulas, that allow to specify a variable (velocity, temperature, etc) along another independent variable ( e.g time or distance).
As for formulas, not every variable is allowed to be defined as a function of another variables. If tables are allowed, you can find the icon of a graph next to the variable you want to define.
Once you click on the icon, a dialogue box appears to define the table. The example below shows a table input for a time dependent temperature boundary condition. The data can be uploaded in CSV format or dynamically manipulated at the interface.
The CSV file should just contain the input values (no title, index numbers…). Every line in the text file will define a row and values separated by a comma ‘,’ will define the columns. As an easy example, the CSV file for the table seen above should be like the following:
Once the CSV file is updated, the variable for each column should be properly set. Values can be manually modified and rows/columns can be added/deleted by right click on any cell. The data from the table can always be downloaded pressing the icon next to ‘Browse files’.
Under advanced settings, two different options appear.
Units: It is possible to define different units for some variable such as temperature or distance.
Out of bounds: By default it is set as ‘Use nearest’. It means that the regions out of the defined range in the table are defined by the nearest value. Hence, the last value in a given coordinate will be kept constant till the end of the domain.
For the CA solver you can as well specify the interpolation type between the given value pairs. The CCX solver uses linear interpolation for nonlinear static and no interpolation (constant steps) for dynamic analyses.
Examples of Table Cases: Vector Variable
For ‘Vector’ variables (e.g velocity) the table upload requires a CSV file with the independent variable and all 3 velocity component values in the order X, Y and Z for each point. Depending on the independent variable we can find two different types of table:
Time distribution: Velocity is assigned for every time instant defined in the table. Along time, a uniform velocity in the faces assigned to the boundary condition is defined. A 4-column CSV file can be uploaded with time and velocity values (t,ux,uy,uz).
Spatial distribution: Velocity is assigned for every spatial coordinate of the Boundary Condition. A velocity profile can be easily defined as seen in the figure below. For a yz plane, a x velocity profile can be defined. A 6-column CSV file can be uploaded with time and velocity values (x,y,z,ux,uy,uz).
Last updated: September 23rd, 2020
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