Contours
Contour representations are critical in marine simulations to understand the response of the free surface to the motion of the vessel. Important representations through are done for the:
Free surface elevation
Creating an isosurface
An isosurface represents points of a constant value within a defined space. The following procedure is used to create an isosurface.
- Click Create an Isosurface
icon in the Geometric Entities Panel. An Isosurface 01 is created under Derived Surfaces - Select Volume Fraction [Component water] under Variables for the Isosurface Variable drop-down list in the Properties Panel > Geometry Tab.
- Select Single value, Below Value, Above Value,and Value Range for the Option drop-down list.
- Enter the parameters for the Value.
In a marine simulation, the free surface helps viewing the wave form. It indicates the height of wave from its calm water position. The free surface is impacted by the Kelvin waves formed due to the hull-fluid interaction. To create the visualization of the free surface elevation an isosurface :
- Select the created isosurface under Derived Surfaces in the Geometric Entities Panel.
- Select Free Surface Elevation under Derived Variables for the Variable drop-down list in the Results Panel.
- Select CAD Surfaces entity deck in the Geometric Entities Panel.
Figure 8.26 - Free surface elevation with volume fraction of water - 0.5
An interesting contour for planing hulls is the surface elevation behind the hull in the wave region. The following steps are used to create this:
- Create an isosurface setting Option to Above Value and specify the Value.
- Select the created isosurface under Derived Surfaces in the Geometric Entities Panel.
- Select hull under Boundaries.
Figure 8.27 - Isosurface with volume fraction > 0.5
Surface distribution
Variables can be plotted on the surfaces of the vessel. such as the ship hull. These variables can be found under Derived Variables under Variable in the Results Panel. The dynamic pressure can be displayed by the following steps:
- Select the boundary on which the dynamics pressure contour is to be displayed under Boundaries in the Geometric Entities Panel (Example : hull).
- Select Dynamic Pressure under Derived Variables for the Variable drop-down list in the Results Panel.
Figure 8.28 - Dynamic pressure distribution on the displacement hull surface
The distribution of dynamic pressure on the hull surface is represented for the planing hull, with the following steps:
- Select hull under Boundaries in the Geometric Entities Panel.
- Select Dynamic Pressure under Derived Variables for the Variable drop-down list in the Results Panel.
Figure 8.29 - Dynamic pressure distribution on the planing hull surface