1. IPAS

SONIA (Simulated Ocean by Numerical Interactive Agents) is a simulation platform dedicated to sea simulation.

It integrates the sea state generation model IPAS (Interactive Phenomenological Animation of the Sea). This model validated with IFREMER can generate regular or irregular multidirectional swells.

IPAS is based onto enaction agents: each phenomenon is represented by an agent (autonomous piece of code, with its own variable and its own execution loop). When a phenomenon needs to know the effect of another one, it places "interaction mediators" in the virtual world, and, later, checks wether another agent has modified the content of the interaction mediator. An interaction mediator is a passive object, with attributes, such as pressure, temperature, spatial position, ...

On the video below, showing a simulation of sea-state from a top view, big orange square represent wave group agents. The small orange dots are interaction mediator. Each wave group needs to know wether it is impacted by the presence of another wave group. To do so, a wave group (lets call it WG1) places interaction mediators in its area of influence. If another wave group WG2 intersects WG1 area, WG2 impacts the interaction mediators (modifies pressure, or water speed, ...). Later, when WG1 retrieves its interaction mediator, the changes on the interaction mediators are used by WG1 to compute modification of its internal variable.

The advantage of this simulation method, is that it maintains mutual ignorance of agents: a wave group needs not to be aware of the existence of other wave groups to behave in interaction with them. Therefore, IPAS agents are able to correctly interact with any agents, including agents not conceived yet.

On the above video, the central black area represents a mesh agent, which is an agent that places a mesh a interaction mediator, in order to draw 3D images of the scene. The mesh agent as no impact on any interaction mediator, and therefore no impact on the simulation results. 3D representation of the simulated sea-stated is visible on the video below.

 2. SONIA

Since IPAS is programmed using enaction-agent, it is then quite easy to add to IPAS simulator new agents representing the behaviour of structures. These structure are, of course, impacted by the sea-state, but can also have an impact of the sea.

The combination of IPAS sea-state simulator and modules leads to SONIA, our virtual test-tank. 

The ambition of SONIA is to be complementary with real test-tank, and not to be a replacement. Large parametric studies can be conducted using SONIA. The ability to interact with the simulation is very convenient in the design phase, to get the feeling of the impact of a specific modification.

As an example, for the development of a large wave energy device such as Bilboquet, SONIA can be use to compute the numerous parameters (weight of the quasi-static part, dimensions, power of the motors, stiffnesses,...) to optimize various criteria (total production, minimum production, rentability, ...)