For this example we will use a pool model as shown in the following figure.
The water level is 1m below the upper edge of the pool walls.
To automatically generate the water pressure from the pool walls we need to use the "Pressure generator". This tool is accessed from the main menu bar: "Generate / Load / Pressure..."
This command will open the pressure generator window:
The following options are available:
- Vertical axis: the global axis for the model verticality, in the direction that the liquid pressure is considered gravitationally.
- Water table level: this option defines the upper and the lower levels of the liquid.
- Liquid density: this option defines the density of the liquid that is pushing on the tanks walls.
- Pressure: this option defines the way in which the pressure is applied on the plane elements:
- Internal: the pressure is applied opposing the local Z-axis of the element.
- External: the pressure is applied in the same direction as the local Z-axis of the element.
- Load case: this option is used to define the load case in which the generated loads will be included.
As seen from the figure above, the pressure loads for some elements are pushing from the outside of the pool. This is because of the orientation of the local Z-axis of these elements.
As we can see, for the plane elements 2 and 3, the local Z-axis is orientated to the outside of the pool and the local Z-axis of element 1 is orientated to the inside of the pool.
There are two ways to correct this:
1. Erase the generated loads, modify the orientation of the local Z-axis for the respective elements (Select the element/ Right click / Modify local axes / Right click until the local axis has the desired orientation) and then regenerate the loads.
2. Individually select each of the incorrectly oriented loads and from the properties list change the orientation by changing the sign.
In the end all the loads should be orientated from the inside to the outside of the pool.