What is in this Article?

1. Introduction

2. Hydrostatic Load

3. Condition of Hydrostatic Load

4. How to create Hydrostatic Load

1. Introduction

Create Load Case & Load is a main steps of Modeling process. This article provides information about a type of load: Hydrostatic load which represents for load or pressure resulting from the static mass of water at any point of floodwater contact with a structure. Following the topics, users will be prepared an overview about the Hydrostatic Load in Akselos Modeler, how to use it and control all the Hydrostatic Load parameters.

Add Load Cases is a part of the Modeling steps in Akselos Workflow to build any simulation model.

Terminologies

2. Hydrostatic Load

Hydrostatic load is a major factor that directly affects offshore structures that are partially or fully submerged in seawater.

* Firstly, see the article - How to add Loads to your simulation model.

This type of load is used to take into account hydrostatic pressure on a solid's surface or shell’s surface when it is fully drafted in fluid.

Figure 1. Hydrostatic Load is applied on a surface of solid component

Figure 2. Shell Hydrostatic Load is applied on shell’s surfaces

Mesh importer default ID convention: Hydrostatic Load Operator is assigned for mesh sideset ID from 330 to 399.

Figure 3. Hydrostatic Load ID Convention

Hydrostatic Load Parameters

Parameters are the main factors of Hydrostatic load. Basic parameters will be showed after users select the Load type; for advanced parameters, users need to create manually.

The parameters of the Hydrostatic Load are as shown in the figure below, including:

• Stored Selection: the stored selection of boundary sets that the load applies on.
• hydrostatic_load_coefficient (kg/m**2/s**2): pressure per length by the liquid, calculated from its density (users input the value).
• water_level_z (m): the level of the liquid in global z-direction (users input the value). Therefore, the local coordinate system of the model should coincide with the global coordinate system.

For surface(s) of shell components, the name of Load will be Shell Surface Load, but other parameters are still the same.

Figure 4. Parameters of the Hydrostatic Load applied on a Stored Selection of solid component

Figure 5. Parameters of the Hydrostatic Load applied on a Stored Selection of shell component

Figure 6. Hydrostatic Load applied on the structure

Formula using for Hydrostatic Load:

3. Condition of Hydrostatic Load

For any load type, there must be an Operator on the Component to define the load type which will be applied on that component.

The operator for Hydrostatic Load is hydrostatic_load or shell_hydrostatic_load and can be created while importing mesh file (the sidesets are already set) or directly created in Akselos Modeler.Figure 7 & 8 will show these operator types

Formula using for Hydrostatic Load:

Figure 7. shell_hydrostatic_load operator for shell surfaces

Figure 8. hydrostatic_load operator for solid surfaces

Figure 9. Sideset ID convention for Hydrostatic Load

In Akselos Modeler, there must be a target that the load will be applied on. In this case, the targets for loads are stored selections. The stored selections for Hydrostatic Load are Boundary Sets selections. See a stored selection for Hydrostatic Load  below.

Figure 10. Stored selections for Hydrostatic load 

Figure 11. Add Load Case

STEP 2: Right-click on New Load Case → Select Add Load …

Figure 12. Add Load

STEP 3: On New Load Case / Load dialog, select Hydrostatic Load / Shell Hydrostatic Load → Click Save.

Figure 13. Add Hydrostatic Load / Shell Hydrostatic Load

STEP 4: On the new Hydrostatic Load 1 / Shell Hydrostatic Load 1 → set Stored Selection: Hydrostatic_Surface or Shell_Hydrostatic_Surface which are already created

STEP 5: On Other Properties → Set value(s) for parameter.

Figure 14. Set parameters for load

Some Related Articles:

• Stored Selections
• How to add Loads to your simulation model