Morrelli & Melvin | Multihull Design - Engineering - Brokerage Morrelli & Melvin Yacht Brokerage - Specializing in Sail & Power Multihull

MM Computational Fluid Dynamics

Our in house computational tools and capabilities allow us to study a wide range of hydrodynamic and aerodynamics problems related to our diverse designs. We have multiple levels of fidelity from lifting line and potential flow panel methods to full RANS calculations to suit each specific case. We work with our clients to identify their performance goals, and then use the tools which best match those objectives. We have the capability to run large simulation workflows on a cloud clusters and get quick turnaround on important design studies.

CFD Applications

  • Resistance and Powering Analysis
  • Hullform Optimization
  • Foil Design
  • Seakeeping
  • Platform Aerodynamics
  • VPP Input Data Generation
  • Fluid-Structure Interaction
Detailed CFD Information

MM Finite Element Analysis

For innovative structures and complex geometries, 1st principles engineering is supplemented with more in depth structural analysis using Finite Element models of the structures. The FEA modeling environments allows us to directly apply various load cases to the geometry and understand the load paths and resultant stresses.

FEA Applications

  • Global Platform Loading Analysis
  • Sub-structure Analyisis
  • Detailed Part Analysis
Detailed FEA Information

MM Velocity Prediction Program

We have the capability to provide performance predictions using straightforward characteristic data input for the vessel, and also higher fidelity 6 degree of freedom predictions which are best suited for race boats and hydrofoil craft. We typically at least run a basic VPP calculation for every vessel we design, however when maximum performance is the objective, North Sails’ RunVPP is our tool of choice. The advantage is its ability to integrate geometry specific, 6 DOF force and moment data from any source, whether that be computational fluid dynamics, experimental testing in a towing tank or wind tunnel, or analytical approximations. Because of that level of fidelity, it can also be used heavily as a design tool to optimize and squeeze every ounce of speed out of the given constraints in design.

Whether for a new vessel, or upgrading an existing boat, we can generate the input data with our in house computational tools, work with outside consultants when necessary (e.g. North Sails’ Flow aerodynamic input), and iterate back and forth with the client to achieve set performance objectives. This type of analysis can reduce time spent sea trialing the boat to tune the setup, and provide a wealth of information about the performance without leaving the dock.

There are two primary ways we use VPP tools. For existing boats where big changes are difficult, we run simulations to assess the influence of weight, aerodynamics, appendage, and sail trim settings on the performance over a range of operating conditions and provide feedback on tuning for best performance. Pre-analysis of course conditions and environments can be included as well for more specific and detailed reports. Secondly, for advanced race boats the VPP serves as a design tool where the general arrangement and positioning/sizing of hulls and appendages can be optimized.