Engineering science gains popularity in sailing

Stig Staghøj Knudsen has sailed all his life and is familiar with the conditions in high-level competitive sport. For the next three years, he will combine this insight with his extensive experience as an engineer developing flow models for ships and wind turbines. The aim is to develop an advanced model, a kind of sailing simulator, that takes into account all physical phenomena associated with sailing. This includes wind and wave conditions and the deformation of the flexible parts of the boat, such as rigging and sails, that takes place when sailing.

“The model calculates the physical effects of wind and waves directly, but measured data is needed to ensure the model’s quality. We retrieve this data from a number of measurements conducted on test trips,” says PhD student Stig Staghøj Knudsen from DTU Mechanical Engineering.

Initially, a model will be built for the NACRA 17 boat type, which is a very special competitive boat that flies on top of the water using four foils. It is an Olympic boat class that is only sailed by the very best athletes.

“The information from the simulation model will subsequently be able to help sailors achieve the optimal settings for the sails and rig, just as it will be able to tell them where on the boat they should ideally be at different sailing conditions,” says Stig Staghøj Knudsen.

Aiming to catch up with the best
The project has been developed in collaboration with the Danish Sailing Association and Team Danmark, who both emphasize that objective knowledge based on mathematical models is necessary today in order to be able to compete with the top sailing nations.

“When it comes to achieving that little bit extra, the big sailing nations like Germany, England, and Australia are way ahead, partly because they have access to many more resources than we do. That’s why we are extremely pleased about this collaboration with DTU, which makes it possible to supplement the sailors’ intuition and experience with objective data from the model. This enables us to either confirm that the sailors are already doing the right thing or get inspired to try new and other solutions to see if they improve the result,” says Andreas Top Adler, performance engineer in Team Danmark.

The project has already created interest among DTU students who are involved in conducting measurements and material testing and developing calculation models. The goal is to build a large advanced sailboat model resembling reality as closely as possible. Work is concurrently being done on a simpler model that does not require the multi-day processing of a supercomputer. In addition, the plan is to develop similar models for other boat types.

“One example could be the 49er, with which Denmark has traditionally done well internationally. The vision is that the new sailboat simulator for sailors in this type of boat should account for some of the sailing hours, so to speak, so that they reach the best possible result faster,” says Stig Staghøj Knudsen.

Contributing to the green transition of maritime transport
In addition to making improvements in sailing, Stig Staghøj Knudsen also hopes that his model will contribute to the green transition of maritime traffic.

“The maritime world is currently exploring how ocean traffic can use alternative driving forces, both in the form of green fuels, but also by equipping large cargo ships with sails or wings. My model can help optimize this work,” says Stig Staghøj Knudsen.

The simulation model is being built as a so-called CFD (Computational Fluid Dynamics) simulation, which takes both the flow of water and air around the boat into account. The CFD model is connected to an FEM, a Finite Element Model, which calculates the deformations of the flexible parts.