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Bottom turn (BT) and cutback (CB) maneuvers A) Surfer drops into a wave at t = 0, with speed 9.2 m/s. B) Bottom turn maneuver at t = 0.79 s with speed = 11.5 m/s. Note speed gain compared to A), and how surfer has rolled board onto the “back side.” C) Transition to cutback at 1.25 s, with speed 10.1 m/s. Speed drops (compared to C) as surfer pitches board and climbs wave face. D) Cutback maneuver, or top turn at t = 2.21 s. Note large amount of spray generated, and how board is now rolled onto the “front side.” The transition from back side to front side delineates the bottom turn from the cutback maneuver. See also Fig 4 and S1 Video for more details of the turn represented in A-D). E) Schematic representation of surfer’s trajectory depicted in A-D).
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We present field results revealing improved surfing performance when a novel approach (“Real Whale”, RW) is used for applying several of the humpback whale’s passive flow control mechanisms, including tubercles, to surfboard fins. It is also the first study presenting evidence of dynamic performance of tubercled designs rotating on all three axes....
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Citations
... These devices provide surfboard manufacturers and academics with direct data on how surfboards perform in real-world ocean conditions [77]. A substantial body of research has demonstrated conclusively that design and materials significantly influence surfboard performance [14,[77][78][79][80]. In these studies, similar to findings in other sports, such as skiing [81], researchers observed that experienced athletes could perceive the mechanical and performance qualities of their equipment when components were modified. ...
The evolution of technologies applied to surfboards has accelerated rapidly in recent years. Not only have the designs of surfboards evolved, but also the materials used in their production have advanced substantially. This progress highlights the need to expand research and deepen knowledge of manufacturing processes, materials, and additives, while quantifying the mechanical performance of materials used in sandwich composites for surfboards. Providing designers and surfers with quantitative performance metrics is essential for meaningful comparisons and for optimizing board designs. This review offers an overview of the primary materials and designs currently shaping the surfboard industry, emphasizing the relationship between material properties and surfboard performance. However, challenges remain in furthering these advancements, and continuous dissemination of knowledge will be crucial for driving significant progress in the sport.
... At the same time, bio-inspired solutions based on sinusoidal tubercles along the leading-edges of lifting surfaces have also gained much popularity. Extensive studies involving the use of regularly distributed leadingedge tubercles or protuberances on aerial/marine vehicle lifting surfaces [12][13][14][15][16][17][18][19][20][21][22], fins or rudders [23,24], propeller blades [25][26][27], compressor and turbine blades [28][29][30], among others, have been conducted since the seminal work [31] on the hydrodynamic design and functions of humpback whale flippers. For a more extensive coverage and review of earlier work carried out on this topic, readers are referred to [32] for further details. ...
Steady-state numerical simulations were conducted to capture the aerodynamic characteristics and flow patterns resulting from a tubercled and non-tubercled wing subjected to various combined pitch and yaw conditions at R e = 1.8 × 10 5 . Pitch angle ranged from 0 ∘ to 25 ∘ , while two different yaw angles of 10 ∘ and 30 ∘ were used. Results show that 10 ∘ yaw angle does not impact upon the lift and drag characteristics significantly, while a 30 ∘ yaw angle leads to substantial lift and drag losses. Additionally, the tubercled wing continues to confer favourable stall-mitigating characteristics even for the larger yaw angle. Finally, despite skewing the flow structures significantly, the 30 ∘ yaw angle also reduces the formations of bi-periodic flow structures, flow separations and recirculating regions along the leading-edge tubercles, suggesting potentially better flow stability and controllability.
... It was observed that oxygen use, paddling cadence and surfboard roll/yaw all increased with increasing water velocity [6]. Additional examples of research in surf engineering include assessing surfer performance on ocean waves [7,8], computational fluid dynamics of fins and surfboards [9][10][11], and measuring flex behaviour of fins in under laboratory conditions [12]. ...
In this paper, we describe the fitting out of a surfboard with inbuilt measurement system and a set of fins instrumented with flex sensors. The inbuilt measurement system consisted of GPS, accelerometers, and gyroscope. Telemetry data were collected during characteristic surfing maneuvers on ocean waves at a sampling rate of up to 80 Hz. Our results indicated that our surfboard with instrumented fins can be used to measure the flex in fins during surfing. Our data showed that both fins flex while on waves (at surfing speed), but not during paddling (at low speed). The commercial sensors recorded fin flex values of up to 10% as the fins are loading and unloading at surfing speeds of up to 6 m/s (from GPS data).
Graphical abstract
... While the shape and movement of dolphins continue to be a source of inspiration (147,158), finned fishes too have drawn intense interest (159)(160)(161), as have sharks (162,163) and rays (164,165). The fluid mechanics associated with rounded tubercles on the flippers of humpback whales have inspired design both below and above water, most notably in the shape of wind turbines, tidal turbines, and even surfboards (56,57,166,167), while the flexible waving of macroalgae has led to the development of kelp-inspired wave energy generators (168). The body design and propulsive systems of other marine life have inspired additional libraries of biomimetic design, including the jet propulsion and shape of squids (51,(169)(170)(171) and other mollusks (172), the movement of siphonophores (173,174), and the bell shape and contractions of jellyfish (51,151,169,(175)(176)(177). ...
The morphology, physiology and behavior of marine organisms have been a valuable source of inspiration for solving conceptual and design problems. Here, we introduce this rich and rapidly expanding field of marine biomimetics, and identify it as a poorly articulated and often overlooked element of the ocean economy associated with substantial monetary benefits. We showcase innovations across seven broad categories of marine biomimetic design (adhesion, antifouling, armor, buoyancy, movement, sensory, stealth), and use this framing as context for a closer consideration of the increasingly frequent focus on deep-sea life as an inspiration for biomimetic design. We contend that marine biomimetics is not only a “forgotten” sector of the ocean economy, but has the potential to drive appreciation of non-monetary values, conservation and stewardship, making it well-aligned with notions of a sustainable blue economy. We note, however, that the highest ambitions for a blue economy are that it not only drives sustainability, but also greater equity and inclusivity, and conclude by articulating challenges and considerations for bringing marine biomimetics onto this trajectory.
... Computer Assisted Design (CAD) and Computational Fluid Dynamics (CFD) allow rapid progression as novel fin shapes and placements can be simulated. Advances in 3D printing technology allow for rapid production and trial of complex fin shapes and profiles [17][18][19]. ...
... The performance of nine different animal-inspired fins was assessed, identifying the short-finned pilot whale fin as performing best in lift to drag ratio and lift force due to its large surface area [19]. A humpback whale fin design demonstrated enhanced rotation rate in comparison to a straight edged fin and to a partially grooved and serrated fin [16,18]. This whale fin also produced the lowest amount of resultant force during turning manoeuvres (force of water pushing against the rider's movement, often referred to as hold) [16,18]. ...
... A humpback whale fin design demonstrated enhanced rotation rate in comparison to a straight edged fin and to a partially grooved and serrated fin [16,18]. This whale fin also produced the lowest amount of resultant force during turning manoeuvres (force of water pushing against the rider's movement, often referred to as hold) [16,18]. ...
Growth in the surfing equipment industry has led to increased scientific interest in this area, yet no current paper has reviewed and synthesized the effects of equipment design on surfing. Therefore, the aims of this study were to: (1) assess the volume and type of scientific literature that is available to the authors specific to surfing equipment and design, (2) summarise all surfing equipment and design studies completed to date specific to outcome measures and key findings and (3) identify knowledge gaps in the topic of surfing equipment design. This review was conducted in accordance with the PRISMA scoping review guidelines. A total of seven electronic databases were searched (PubMed, Embase, CINAHL, SPORTDiscus, Web of Science, SCOPUS, and Ovid). Google Scholar was also searched for grey literature. Inclusion criteria were mention of surfing equipment and relevant surfing outcome measures (physiological and mechanical). Exclusion criteria were no full text availability and works not available in English. Results from these articles were then extracted, summarised and presented. A total of 17 articles were selected for review and organized by theme of board, wetsuit and fin. Fin and wetsuit design were the most prominent themes (seven studies each respectively). Most were written within the past 5 years and written in the USA. Fin design studies were largely computational, whereas board and wetsuit design were mostly field and laboratory based. Within each study theme there were consistencies in outcome measures and measuring devices. Board design studies focused on paddling efficiency (VO2 and HR). Wetsuit design studies primarily assessed thermoregulation, and less so muscle activation and paddling biomechanics. Fin design studies focused on fin shape and configuration to assess lift and drag properties. Three key themes of board, wetsuit and fin design were noted; from this the authors were able to identify several knowledge gaps such as a lack of standardisation in equipment controls and study design procedures. Alongside improving standardisation, the use of wave pools presents as an area of interest in future research.
... Field research materials and methods are discussed in more detail elsewhere [1,5,6]. The research involved surfers of 4 different skill levels as defined in Reference [7], including intermediate (Level 6), expert (Levels 7 and 8) and WCT, or World Surf League Men's World Championship Tour (Level 9). ...
Compared to other Olympic sports, little research exists on competitive shortboard surfing-especially research comparing field and numerical data. In this paper, GPS sensors with 9-axis motion sensors were used to collect data on nearly 2000 surfed waves. Data were collected from four surfers of differing skill levels, ranging from intermediate/advanced (Level 6) to top-ranked professional (Level 9). The results revealed a positive correlation between surfer skill level and roll/pitch/yaw rates during a cutback. Some surfers used two different fin types: a standard commercial fin (C), and a 3D-printed, humpback whale-inspired fin (RW). Statistically significant cutback performance improvements were seen when surfers used the RW fin. Because of the skill level differences suggested by the field data, dynamic computational fluid dynamics (CFD) analysis was performed to simulate cutback maneuvers at three different rotation rates (roll/pitch/yaw). Sustained resultant forces relative to the rider direction were lower for RW fins during the turn, suggesting a less-skilled surfer could generate faster and more powerful turns using RW fins. Field results also confirmed that a skill Level 8 surfer performed closer to skill Level 9 when using RW fins, but not control fins. Surfers experienced more stability using RW fins, and CFD results confirmed RW's ability to dampen the effects of turbulent flow.
This research aimed to determine whether accomplished surfers could accurately perceive how changes to surfboard fin design affected their surfing performance. Four different surfboard fins, including conventional, single-grooved, and double-grooved fins, were developed using computer-aided design combined with additive manufacturing (3D printing). We systematically installed these 3D-printed fins into instrumented surfboards, which six accomplished surfers rode on waves in the ocean in a random order while blinded to the fin condition. We quantified the surfers’ wave-riding performance during each surfing bout using a sport-specific tracking device embedded in each instrumented surfboard. After each fin condition, the surfers rated their perceptions of the Drive, Feel, Hold, Speed, Stiffness, and Turnability they experienced while performing turns using a visual analogue scale. Relationships between the surfer’s perceptions of the fins and their surfing performance data collected from the tracking devices were then examined. The results revealed that participants preferred the single-grooved fins for Speed and Feel, followed by double-grooved fins, commercially available fins, and conventional fins without grooves. Crucially, the surfers’ perceptions of their performance matched the objective data from the embedded sensors. Our findings demonstrate that accomplished surfers can perceive how changes to surfboard fins influence their surfing performance.
The propeller is a fundamental part of an aircraft powered by the turboprops, piston engines, or electric motors. A propeller that spins efficiently through air directly results in environmentally friendly and cost-effective flights. As a part of this novel study, the effect of leading-edge tubercle amplitude and wavelength on propeller efficiency was explored. The effect of leading-edge tubercles on various propeller solidities was also investigated. In addition, the effect of leading-edge tubercles on propeller diameter-to-pitch ratio was also studied for a wide range of advance ratios and rotational velocities. Small-sized aeronautic propellers were considered for the present study. The results predict an increase in efficiency of the modified propellers in comparison with the baseline propellers for all the cases considered in the present study. Therefore, a propeller-driven aircraft with the modified propeller installed in place of the baseline propeller, with an increased thrust-to-torque ratio, will have the potential for a higher maximum rate of climb, lower time to climb, higher absolute and service ceilings, and higher range and endurance, leading to greener and cost-effective flights.
