From Sailing Design Ingenuity to Cyclor Power with CFD

The America's Cup, known as the pinnacle of yacht racing, is back and creating more excitement than ever. It captures the interest of sailing enthusiasts and sports fans alike. The 2024 edition promises thrilling innovations and intense competition, making it a spectacle not to be missed. This race, often called the "Formula One of the sea," is a test of speed and weather tactics and a showcase of cutting-edge nautical innovation.

Central to these innovations are the design and technology of the boats themselves. From the sleek, optimized hulls to the gravity-defying hydrofoils and the innovative use of cyclists, each element plays a crucial role in shaping the future of competitive sailing. But how do marine engineers tackle these challenges? This is where computational fluid dynamics (CFD) steps in, guiding the way from the drawing board to the waves.

Optimized Hull Design for Stability

The hull of a sailing vessel serves as its pivotal component, determining how effectively it slices through water and adapts to the ever-changing sea. In the competitive setting of the America's Cup, teams have adopted various AC 75 hull designs, each tackling the inherent design challenges in unique ways. Engineers aim to lessen drag by meticulously refining the hull's shape, enabling it to glide more smoothly through the water. The goal is to balance speed and stability, ensuring the boat can perform well across various sea conditions.

Hull optimization focuses on shaping the boat's underwater portion to minimize drag while maximizing stability. This involves calculating the ideal curvature and surface area to achieve the right balance between these two forces.

Hydrofoil Designs to Fly in Water

Hydrofoils are a revolutionary technology in the sailing world, bringing a new era of high-performance and gravity-defying speeds to the sport. The principle behind hydrofoils is akin to the mechanics of airplane wings, leveraging simple physics—specifically, Newton’s 3rd Law. Hydrofoils lift the boat's hull above the surface by generating a pressure difference above and below the foil as they slice through the water. This technology dramatically reduces drag from the hull, enabling boats to achieve speeds that were once thought impossible.

The design and implementation of hydrofoils come with their share of challenges and constraints. A critical aspect of hydrofoil technology is managing drag, both in the water and the air. The design goal is to minimize the surface area in contact with these elements to reduce drag significantly. However, achieving lift and the initiation of foiling is more complex with smaller foils, presenting a trade-off between speed and stability. This balance between risk and reward is fundamental to the design process of hydrofoils, according to Renato Conde of the Denmark SailGP Team.

The design is further complicated by phenomena such as cavitation—a boiling, bubble-effect around the foils at high speeds—which can dramatically reduce efficiency and stability due to the reduced ability of the foil to 'grip' the water.

The Rise of Cyclors

The America's Cup competition has evolved from relying on traditional grinders, which use arm strength to operate hand cranks, to a modern strategy that harnesses the unrivaled endurance and strength of cyclists or cyclors.

For the upcoming 37th America’s Cup, INEOS Britannia's crew is intensively training alongside the INEOS Grenadiers cycling team on land. This innovative preparation focuses on leveraging leg power, with crew members operating the boat's hydraulics using stationary bikes integrated into the 75ft carbon-fiber hull. The team comprises eight cyclors, including four elite former rowers, - Matt Gotrel (Olympic champion Rio 2016), Matt Rossiter, Ryan Todhunter, and Harry Leask (Olympic silver medallist Tokyo 2020), although only four cycling sailors will compete in each race to propel the craft.

Notably, human legs are significantly stronger and more enduring than arms, allowing cyclors to sustain power outputs of up to 500 watts for 20 minutes and achieve peak sprints of 1,800 watts. Such sustained high power output allows for better and more consistent trimming of the sails, resulting in higher speeds and more agile maneuvering. This new energy generation technique comes with new challenges; addressing them before production is important.

The Role of CFD

Optimizing a hull, designing hydrofoils, and integrating cyclor power into a cohesive, high-performance system presents a complex matrix of engineering challenges. This is where CFD becomes invaluable. Through simulations, CFD can anticipate and solve these vessels' hydrodynamic and aerodynamic challenges, enabling designers to iterate rapidly and precisely.

1. Optimized Hull: CFD facilitates fluid flow analysis around various hull shapes under different conditions, enabling designers to comprehend and reduce resistance, ultimately enhancing both speed and stability. By optimizing the hull design, it is possible to reduce fuel consumption by approximately 16.5%.
2. Hydrofoil Design: With CFD, designers can simulate the lifting forces, analyze cavitation risks, and assess the overall impact of hydrofoil designs on boat performance. This is critical for balancing speed enhancements with control and stability.
3. Cyclors: Integrating cyclor power poses unique design challenges, including the optimal positioning of cyclors for aerodynamic efficiency and the transmission of leg power to sail propulsion. Through CFD, the effects of these configurations on air and water flow can be scrutinized, ensuring that the addition of cyclors effectively translates into increased performance.

Innovating Competitive Sailing Design With Cadence Fidelity Fine Marine

Accurate resistance calculations and propulsion modeling are essential for refining hull designs and striking the optimal balance between speed and energy efficiency. By minimizing resistance to water flow, teams can greatly enhance their yacht's speed and overall performance. This optimization is achievable through the use of the Cadence Fidelity Fine Marine, a leading solution in marine design and engineering software tailored for the intense requirements of high-stakes events like the America's Cup. By leveraging the extensive features of Fidelity Fine Marine, America's Cup teams can explore new frontiers in yacht design and engineering, driving innovation and competitiveness in their pursuit of victory.

Fidelity Fine Marine can enhance the design of hulls and hydrofoils by accurately simulating the interactions between air, water, and the various surfaces of the vessel in realistic conditions. This includes examining fluid-structure interactions to gain valuable insights into speed and stability. Meanwhile, for the cyclor revolution, Fidelity Fine Marine can optimize the boat's aerodynamics by modeling the airflow and disturbances created by cyclists, allowing for enhancements in speed while ensuring handling and overall performance are not compromised.

Looking Ahead to the Future of Sailing

As we prepare for the 2024 America's Cup, it's clear that we're at the cusp of a major change in the sailing world. The blend of age-old sailing skills and cutting-edge technology is not just a fleeting phase; it's revolutionizing how competitions are tackled. It's not just about racing to the finish line anymore; teams are using advanced technology like CFD to creatively enhance their tactics and push their boats further than ever before. 

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