In many situations choosing the best way to integrate CFD into an existing design process can have as much influence on the effectiveness of the results as the technical aspects of the CFD solution itself. As we saw in issue two, with the America’s Cup bulb, CFD can be a great tool in optimising a design at its inception but that might not be the best way to get value out of CFD in your design process. Over the next two editions FLUID is going to look at two different ways we integrated aerodynamic RANS analysis into the design process of America’s Cup sails. Read more

From an Euler solution, the next simplification is to ignore vorticity in the flow. This allows the velocity field to be represented as the gradient of a scalar function – f the velocity potential. A solution can then be calculated for the potential that describes the flow around a body. This is generally achieved numerically by using panels on the surface hence many potential methods are known as panel codes.

For a Naval Architect, potential flow can be a very useful tool but it is important to recognise its limitations. As it ignores vorticity it does not give good results in areas of turbulent flow and has no capability for solving boundary layer effects although many potential solutions use adjustments account for these limitations. A lack of viscosity, both real and numeric does mean that wave patterns are propagated away from the hull surface so a potential method will be far superior for wash studies. Potential codes are also an order of magnitude faster than RANS so a potential solution so can generally generate a result in a relatively quick time on a standard pc. See whole thread

Many Naval Architects see CFD as the domain of the ‘top end’, only used by Navy, America’s Cup teams and ultra high performance high budget enterprises. This perception scares designers away from CFD and often people think projects aren’t complicated enough to benefit from the type of analysis CFD can provide. But there is no reason for this to be the case with NHFD providing the hardware, software and specialist knowledge all a Naval Architect needs is a desire to make his design the best it can be. See other myths