SYRF Publishes Results from Downwind Aero Project 2, Approves Funding for New Research Studies

Downwind Aero researcher JB Braun available for a conference call on Wednesday, Dec 7th, Phase 1 of new Pcubed study approved to evaluate panel vs. RANS codes, 14 Meter hull design made available for research, and performance tracking data projects described in presentation made at the Yacht Racing Forum

Newport, RI – In the last few months there has been tremendous activity in both existing and new projects supported by the Sailing Yacht Research Foundation (SYRF). The results of these programs will further enhance SYRF’s mission to assist in the science behind handicap racing.

Backpressure Observed on TP52 at TWS16 at AWA 35

First, the second phase of the Downwind Aero Moments and Forces project has been completed, with the final report and results now published and available in the SYRF Library. This Fluid Structure Interaction (FSI) study was designed and carried out to improve the understanding of downwind aerodynamic performance. With Phase 1 (published in February 2016) providing the moments and forces for a range of downwind sails at Apparent Wind Angles (AWA) greater than 130°, Phase 2A was designed to expand the initial dataset to include tighter AWA data with simulated custom tight angle sails, compared to the Phase 1 sails which were based on produced sail designs. Phase 2B sought to quantify the effect of increasing and decreasing the girths of the mainsail and gennaker; using the sail designs from Phase 1 as a base, Phase 2B separately morphed the girth of the mainsail and gennaker, re-running the AWA and True Wind Speed sweep from Phase 1 to capture geometric effects of such changes.

“The approach of Phase 2 proved valuable in developing a comprehensive collection of the total forces and moments on each sail as well as total sail plan,” said lead investigator JB Braun of North Design Services. “Supplementing the wider AWA range dataset produced by Phase 1 with Phase 2A’s tighter AWA Code 0 type sail data helps better define the relationships and crossovers between Code 0, A2, and A3 sails through a range of wind angles and speeds. In particular, Phase 2A demonstrates how the crossovers change as the girth of a Code 0 is modified.”

The value of this study for handicappers is that in combining the results of Phase 1 and Phase 2A, it yields a more complete dataset that covers a full range of offwind sailing angles. Phase 1 provided data across a range of AWA from 45 to 150° for three types of gennakers across a TWS of 8, 12, and 16 knots. Phase 2A provided data for two types of Code 0 sails (a Code 0 without girth restriction and a Code 0-75% conforming to a 75% girth rule) across a range of tighter AWA.

Braun will be available this Wednesday, December 7th for a call-in conference where he explains the value of this study and is available to answer questions. Details for this special event are available as follows:

SYRF – Ask JB
Wed, Dec 7, 2016 10:00 AM – 10:45 AM EST

Join this meeting from your computer, tablet or smartphone:
https://global.gotomeeting.com/join/900789453

You can also dial in using your phone:
United States +1 (872) 240-3412

Access Code: 900-789-453


Other news is that the Board has approved the funding for the initial exploratory phase of the Performance Prediction Plan, or P cubed, an ambitious research project that will help to identify the tools and methods needed to create a comprehensive performance prediction plan applicable across a wide variety of boat types. This initial phase will evaluate the results generated by both panel and RANS code tools to determine if the panel codes, which are more cost-effective, are of sufficient accuracy to use in the second phase of the project.

Coming from the completion of the Wide Light Project, SYRF Technical Director Jim Teeters has worked with designers on the SYRF Advisory Council to develop a standard 14 Meter hull form that can serve as a test base to evaluate future CFD-based research projects. SYRF will publish this hull form online and encourages all to share their results from the published test matrix. “The goal is to encourage an open source collaborative environment within the yacht design community,” says Executive Director McKenzie Wilson.


Lastly, last week Wilson represented SYRF in a panel discussion on Performance Data Collection Technologies at the Design and Technology Symposium of the Yacht Racing Forum held over November 28-29 in Malta. The support of the KND performance analysis project was described, along with an active and lively discussion on the value of this topic in front of a packed room of international and influential designers, sailors, organizers, technologists and media.

“We have not been to this event in two years,” said Wilson, “and by most accounts this was the most successful edition yet. We not only helped educate more people about SYRF and what we do, but also made and intend to develop some valuable contacts among potential donors of both new datasets made available for the Library as well as funds to help support our efforts.”

“These projects demonstrate the tremendous efforts made by our Advisory Council, Board and research associates at pursuing science in the interest of sailing,” says Chairman Steve Benjamin. “We hope that you remember SYRF in your year-end plans for charitable donations, as there is no better value in supporting an organization that strives to help improve fair racing in offshore sailing.”

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