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Computational Fluid Dynamics (CFD)
Navatek is a world leader in the application of computational fluid dynamics (CFD) to the design of ship hull forms, ocean structures, underwater lifting bodies, and coupled hydrodynamic systems. Navatek employs a full complement of tools from simple empirical models, through proprietary medium-fidelity potential flow codes, to commercial Reynolds Average Navier Stokes (RANS) codes to perform these analyses. Navatek’s philosophy in CFD is “The right tool for the job”. Unique to Navatek is a history of full-scale sea trials that have proven the utility and validity of our CFD tools. Navatek has a wide array of experience in using the commercial code CFX in the design and analysis of ocean systems. From small, high-speed planing boats to large, zero-speed structures, the code has proven extremely accurate and robust. As with any complex tool, the key to its use is the knowledge of the user. Because of the complexity of most real world problems, simply operating the code is not sufficient; a deep knowledge of the both the physics embodied in the underlying equations and the quality of the numerical solution is imperative. Navatek is co-developer of the potential flow code Aegir. Aegir is a NURBS-based, “panel-less”, high-order, boundary-element method for the computation of steady and unsteady forces and motions of systems operating at or near the free surface. Aegir is fast, able to operate on a desktop machine in a manner of minutes for steady wave resistance solutions and hours for long-time seakeeping simulations. However, Navatek’s 128 node cluster allows for large batches of runs to be performed in parallel. This capability coupled to Navatek’s in-house, automated design optimization process and shape morphing allows for optimal designs with a quick turn-around. Navatek is also co-developer on the module-based, coupled mechanical integration tool NavaSim ® . NavaSim allows, via a series of connectors to external codes, the simulation of large complex, nonlinear problems. Because the modules are kept completely separate, each tool can be left to do the job it was meant for: CFD for hydrodynamic forces, elastic model for impact calculations, high speed corrections for planing boats, control actuation for actively controlled systems, waterjet models when appropriate, linkage models when objects are connected, etc. Navatek leads the industry in using both medium and high fidelity methods for design and simulation of active control systems. Through the use of NavaSim and Aegir, the exact interaction between vessel and actuation system can be modeled. Because of the accuracy of the tools, a high degree of confidence can be given to any solution that is produced. This, in turn, leads to reduced “tuning” of the system at sea which is costly and time consuming. Because of the modularity of NavaSim, control logic can be implemented as fully compiled executables. This allows Navatek to test proprietary code while maintaining the privacy of those algorithms.
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