SUPR
Sailing Dynamics
Dnr:

NAISS 2024/5-532

Type:

NAISS Medium Compute

Principal Investigator:

Lars Larsson

Affiliation:

Chalmers tekniska högskola

Start Date:

2024-11-01

End Date:

2025-02-01

Primary Classification:

20303: Vehicle Engineering

Secondary Classification:

20306: Fluid Mechanics and Acoustics

Allocation

Abstract

Chalmers is a National Sports University and is engaged in research within Sports and Technology. Earlier, sailing was the largest area, but due to lack of qualified supervisors after my retirement in 2020 it is no longer a focus area. A presentation of the sailing work carried out within the center may be found on the link: https://www.dropbox.com/scl/fi/x0mxjxrex2wu28hmxzclt/Presentation-S-T-hemsida-pdf.pdf?rlkey=ibhxlt2tp365x5xrk9z0q92mb&dl=0. The presentation introduces a large number of projects, and the work has resulted in 34 external publications, 2 Licentiate theses, 14 MSc theses, 4 BSc theses and 6 project reports. Almost all work within the center has been numerical, so large computer resources have been required. The work carried out recently is presented in the Activity report, where it appears that the only remaining sports sailing project is Adam Persson’s PhD project, which is the most fundamental one of the sailing projects in the Centre. He develops a numerical technique for sailing yacht performance prediction in waves based on Computational Fluid Dynamics, strongly coupled to 6DOF rigid body dynamics (CFD-VPP). This calls for massive computer resources. As explained in the Activity report, there is a very large interest in sail-assisted ships at present. Considerable fuel savings (and emission reductions) are possible, and many projects are underway worldwide. Now, Adam’s CFD-VPP technique may be readily expanded to this area, and this development will be done after the completed PhD exam. However, already now a development of the aerodynamic model is underway in the PhD project by Karolina Malmek. Since sail-assisted ships will have many sails in one or two rows along the ship, sail-sail interaction will be important. In her Licentiate project Karolina has developed a sail model for this purpose, assuming undisturbed inflow (see the Activity report). At present, she is modifying the proposed method to make it more robust and will validate it against wind-tunnel data. This calls for some 3D CFD computations to account for wind tunnel corrections. Later, she will include the velocity disturbance from the hull and the vertical velocity gradient due to the atmospheric boundary layer. Computational resources are thus required mainly for Adam but also for Karolina. For Adam large resources will be required to carry out the final computations for his PhD project: a performance prediction for a sailing yacht in waves including the dynamic sail model. Note that large resources were allocated in the previous project, especially since the allocation was increased in September-October, but they could not be fully used, as explained in the Activity report. These massive resources will now be required in November-December and a smaller allocation will be needed in January 2025 to finalize the project. This continuation project therefore has a duration of three months. Karolina will need considerably less resources, as her CFD computations will be for a simpler steady state problem without rigid body motions.