Driving force, heeling force, and turning moments predict and optimize sailboat performance. Calculating these correctly could mean the difference between winning and losing at the 2008 Olympics.
That’s why Finland-based sail maker WB-Sails chose Flomeric’s EFD.Lab fluid-dynamics-simulation software to develop and optimize the sails for its Star and Finn-class Olympic sailboats. “Our traditional panel codes predict sail forces reasonably well in the upwind case, when flow separation is not a major factor, but we were desperate for something more powerful to predict 3D airflow and sail forces on downwind legs and in the lighter winds that we expect in Beijing,” said Mikko Brummer, head of R&D at WB-Sails.
Unlike other programs they tested, EFD.Lab provided the direct CAD-to-CFD technology and automatic- mesh generation needed for fast turnaround times. The program also threw in a couple of surprising facts the team was unaware of 3D airflow phenomena they didn’t know existed and that the mast, usually considered a necessary device that adds drag, actually adds to the boat’s driving force.
The software pinpoints problem areas in sails where flow separation is likely to occur. Flow separation reduces the driving force in the sail and increases drag. The software allows nonuniform airflow conditions to be specified at the entry plane, representing the atmospheric boundary layer at the sea’s surface. Combined with the boat’s speed, the result is a complex “sheared” and “twisted” wind pattern approaching the sails. EFD-Lab’s built-in graphical postprocessor lets airflow trajectories and pressure forces be visualized with full 3D animation.
Go go Gadget ... Helicopter!
Renaissance inventor Leonardo da Vinci is thought to have designed the first verticalflight machine an aerial screw in the 1480s, according to Italy’s National Museum of Science and Technology.
On May 25, the world’s smallest oneman helicopter flew over Da Vinci’s birthplace, the city of Vinci near Florence, in tribute to the inventor.
The GEN H-4, designed by Gennai Yanagisawa in the late 1990s, is a 75-kg (165-lb) counterrotating helicopter. The aircraft consists of a chair, handle bar, and footrest. Four engines let the helicopter stay in the air for 30 min and reach top speeds of 56 mph.
The 75-year-old Yanagisawa, who runs an electronics-equipment company in Japan, always wanted to fly over Da Vinci’s birthplace since the concept for his copter came from Italy. “I feel like I’m greeting an ancestor. I hope Da Vinci would be pleased.”
Guinness World Records has confirmed that the GEN H-4 is the smallest in the world in terms of weight and its 3.9-m rotor length.
Free motion hardware for students, researchers
Performance Motion Devices’ (PMD) iBot, Motion Control for Higher Education program is an innovative approach to creating a greater understanding of motion and motor control. Students, researchers, academic groups, and organizations can receive free motion- control hardware for academic and R&D applications using motion control.
By reviewing all of PMD’s motion- control products, program participants can determine which best suits their project. Participants submit applications via the company’s Web site around the first of each month. PMD reviews and judges the applications on technical innovation, uniqueness, and overall feasibility and awards the most promising/highest-potential project free motion-control hardware specific to the project. Entries not selected can be resubmitted. PMD follows the progress of the project through to completion. Program criteria includes:
Individuals, students or student teams, nonprofits, and university researchers, both in the U.S. and internationally can apply.
The project must include a unique motion-control component/ application.
Submissions, via PMD’s Web site, must be made by the 15th of each month. Winners will be announced on the 1st of the following month.
Fredrik Lf and Anders Ekstrm are Swedish medal hopefuls in the Star class in Beijing. 3D airflow analysis using EFD.Lab reveals massive flow separation behind the Star jib sail at angles near stall.
Inventor Gennai Yanagisawa stands alongside Gen Corp.’s Yasutoshi Yokoyama as he sits on the GEN H-4 near Da Vinci’s birthplace in Vinci, Italy, on May 25.