Alexander Simonis om dagens analysverktyg och hur dessa går att använda mot ORCi och IRC reglerna

Som "gammal" beräkningsingenjör så har alltid de moderna beräkningsmetoderna fascinerat mig. Koppling mellan flödesberäkningar och hållfasthet är ganska spännande vetenskap. I segelbåtsdesign för respitsegling så gäller det ju också väga in de olika respitreglerna.
Jag ställde några frågor till Alex Simonis som är ena halvan av design paret Simonis Voogd om hur detta egentligen fungerar.
För det mesta så ser man dessa bilder i marknadsföringen av de olika designbyråerna. Man får ofta intrycket att det är verktygen som löser det till designern.
Här är en av mina frågor och Alex syn på det hela.

I understand that you use a lot of modern tools like CAD, FEA and CFD analysis when analyzing the designs. How do you connect those analyses to the different rules like IRC and ORCi?

"CAD and FEA are really drafting and constructing tools; their rating input is pretty much limited to the weight and Cg’s it produces.
CFD touches much more on the whole core of yacht research as it can be viewed as a "virtual test tank”.
IRC as a close rule brings it’s own difficulties where a lot of data analyses of comparative and successful IRC designs is important. The way the rule is sort of secret and the way it deals with certain undisclosed factors (like the hull factor for example). Leave a lot to be desired as the lack of transparency simply cannot get rid of the uncomfortable feeling many designers and owners have that it is subjective.
This is ultimately going to be the downfall of IRC, it can’t operate as a grand prix rule if it doesn’t deal with this to everybody’s satisfaction. ORC on the other hand has been pro-active to turn the IRC tide and is gaining a deserved momentum again. For ORC the key is going to be to see that their VPP’s are getting more an more accurate by constant research and keeping on top of what is happening in order to more quickly react or even anticipate where yacht design is heading to so that they can deal with it fairly.
Next to that, they need to keep working on simplifying the rating system which is applied during races striking a balance between accuracy and simplicity. It has come a long way from the wind average scoring system, which needed an average Einstein with a PC and constant inputs onboard if you wanted to know what was happening on handicap during a race.

From a designers point of view CFD is a great tool, but still has some way to go on validating against real life situations.
Only be working with such a tool on a constant basis will we get a better understanding of its possibilities and limitations. At the moment it is great to do comparative studies and to improve finer details such as foil/hull and foil bulb interaction. The whole set up on improving hull shapes and feeding the calculated resistance curves back into the VPP is there but is fair less straight forward. "
Med CFD, Computational Fluid Dynamics, verktyg kan man räkna på hur det strömmar kring en kropp. Färgerna här visar i vilken grad strömningen är laminär eller turbulent. Rött är med all säkerhet turbulent strömning.
På den här bilden visualiseras häck och bogvåg. Man kan alltså jämföra olika kroppars "drag".

På den här bilden kan man se hur en bula på skrovet skapar turbulens.

Den här bilden visar en fena på en flerskrovsbåts ponton.