Energy Saving Devices Structure


Nowadays, the structure of Energy Saving Devices (ESD) is not reviewed by Classification Societies. Only its attachment to the hull is considered. From a safety point of view, it is important to demonstrate that the ESD does not represent any hazard for the structural element on which it is mounted and for other neighboring hull outfitting. The main challenge is to evaluate the loads applied on the ESD structure in sailing conditions, because the regulations give no guidance to validate its design. In order to consider the seakeeping behavior of the ship and to estimate these dynamic loads, a complete assessment procedure is proposed:

           1)   Perform CFD analysis in steady flow to optimize design and power gain estimation,

           2)   Apply a methodology to evaluate maximal forces on ESD in navigation conditions,

           3)   Apply a methodology to define a Design Wave leading to these forces,

           4)   Perform a second CFD computation using the Design Wave defined in stage 3,

           5)   Carry out a structural analysis:

                          - with Finite Element method, using forces determined in stage 2

                          - or by pressure distribution, provided by CFD computations in stage 4.