Hexapod

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The Chair of Ocean Engineering at the University of Rostock has a long-standing research expertise in areas such as underwater systems, fluid-structure-environmental interaction (hydrodynamics) and underwater sensor technology. One of the most important challenges in assessing any type of ocean technology is a comprehensive hydrodynamic analysis, i.e. the study of the interactions between wind, current, sea state and object to be deployed. Although many questions can be answered at least partially by means of numerical simulations, the execution of true-to-scale model tests, e.g. when it comes to seakeeping behaviour, is still inevitable.The use of a hexapod enables the implementation of a so-called "hardware-in-the-loop" system. By using a hexapod, an object is not directly examined whilst performing in waves. Rather, the seakeeping behavior of a structure is first approximated numerically, in order to then impose the determined motions onto the object itself or a model of it. This in turn allows dynamic effects and especially nonlinear hydrodynamic parameters to be determined, which are subsequently incorporated into improved numerical analyses and simulations. The use of a hexapod for the simulation of motions in 6 degrees of freedom thus offers in many ways a cost-effective alternative to the classic seakeeping basin with elaborate wave making technology.Also, for systems that are not exposed to waves, the hexapod, in conjunction with existing laboratories, offers completely new possibilities regarding the determination of dynamic fluid forces acting on fully or partially submerged systems. Such forces, as well as the associated hydrodynamic masses, damping and other coefficients of interest for objects undergoing forced motion sequences, cannot be investigated without the use of the hexapod. In addition, the portfolio of possible experiments is extended to include the investigation of highly complex, dynamic flow processes. In particular, the possibility of examining the flow as well as flow-induced forces during high-precision motion sequences while changing the flow direction is of paramount interest. In addition, fully automatic tests covering a wide range of relative positions between objects and flow, without having to temporary shutdown the wind tunnel are possible. As a result, the time required for testing is reduced whilst the quality of the measurement increases. Hence, test campaigns can be made much more efficient.The hexapod, in conjunction with the existing laboratory facilities of the chair, will significantly expand the experimental portfolio and thus opens up completely new perspectives with regards to innovative, future-oriented research in the field of ocean technology at the University of Rostock.