…no truly. Let me tell you more about it. I am also sorry for the lack of posts. This is due to it becoming apparent that some of the most avid readers are from the bike industry and we started seeing our designs under random other brand labels. The tenor of the blog will also thus change somewhat and will cover releases, rather than work in progress, and team and rider stories. Stay tuned.
Back to the subject matter;
Bicycle aerodynamics are very difficult. We all know that most of the aerodynamic drag comes from the rider, and that the frame/wheels do not contribute more than 20-25% to the overall bicycle drag. It is also convenient to think that there isn’t much benefit to improving the bicycle frame and wheels aerodynamics since the assumption is that the current aerodynamics solutions for bicycles are so good that any further improvement is deep into the “diminishing returns” area.
However, improvements are possible, but due to the peculiarities surrounding low speed, low surface area aerodynamics (low Reynolds number), they are very hard to identify and implement. Air behaves very differently in the bicycle racing realm than it does around cars, Formula 1, or air planes. The basic principles are the same, but the “devil is in the detail”. This minor detail is called induced drag. None of the current bicycle designs come close to solving this problem. While just about any medium to high aspect ratio (how long it is versus how thick it is) airfoil, or even truncated airfoil (cf. Kamm) will do very well in zero to shallow angles of attack (yaw), none of them can cope well with higher angles of attack starting at about 5 degrees…or better said, they are all as good as each other with very minor differences. See the image below for visualisation of induced drag at 5 degrees angle of attack. This airfoil is otherwise a very well performing design.
We will change the lay of the land and deliver the first truly aerodynamic bicycle design, and the first ever airfoil designs that work at the bicycle scale. This is not an empty (vacuous) boast, so how will we do that?
See the press release below…
Velocite and NCHC set to revolutionize aerodynamic bicycle design
Velocite Tech Co. Ltd. (Velocite) and the National Centre for High Performance Computing (NCHC), a laboratory under the umbrella of the National Applied Research Laboratories (NARL), Taiwan, have signed a cooperation agreement aimed at solving and developing an aerodynamically optimized bicycle – designed completely by a supercomputer.
Following an exhaustive search for a development partner, Velocite has partnered with the NCHC to develop the next generation of aerodynamic bicycles using specially developed algorithms employing both Computational Fluid Dynamics (CFD) simulation and Genetic Algorithm (GA) optimization engines conceived and written by NCHC researcher Dr. Matthew Smith and a team of researchers from the Applied Computational Engineering (ACE) and Applied Scientific Computing (ASC) divisions.
Among the significant resources that are made available to this joint project is the GPU supercomputer housed within the NCHC location in the Tainan Science Park. This GPU based supercomputer was constructed and configured by NCHC staff and possesses more than 240 Tesla computing devices and approximately 8.4 TB of total system memory, making it one of the most powerful computer systems in the world.
The major determinant of the level of detail, and therefore the real-life accuracy, is the number of cells in a 3D mesh that defines the object that is being studied. Previous CFD work conducted on bicycles was limited to approximately 20 million cells. Because software for the collaborative project is written by NCHC researchers specifically for the GPU supercomputer, the 3D mesh employed by the CFD solver can potentially have in excess of 2 billion cells. The ultimate goal of the NCHC is to simulate the complete bicycle in motion, including a moving and pedalling rider derived from 3D scans.
Optimization of the design will be conducted by a genetic algorithm where the final solution evolves over successive breeding generations. It is expected that approximately 500 generations will be required, resulting in at least 7500 individual CFD simulations. This means that during the course of optimization at least 7500 individual aerodynamic bicycle designs will be evaluated and tested automatically by the artificial intelligence GA for aerodynamic performance before the optimal design is found. “Without the supercomputers and our fast CFD algorithms, this task would be impossible.” said Dr Smith. Even so, the final simulation run will take in excess of 25 days to compute – the same task, running on a standard desktop PC, would take over 150 years to complete.
“We are absolutely thrilled to have NCHC and Dr Smith engaged with Velocite to perform this much needed research on bicycle aerodynamics.” said Victor Major, Velocite CEO. “After spending considerable time looking for suitable partners and staring in the face of staggering costs for this type of work, we were forced to either reduce the scope of development, or to abandon the aerodynamic optimization project altogether. With NCHC, Dr Smith and his team on board, we now have more engineering and development capability at Velocite than we ever expected to obtain.” also said Mr Major.
Due to the groundbreaking nature of this joint development project significant new technological and design breakthroughs will be achieved. Velocite and NCHC will publish some of the findings in relevant scientific and engineering journals, detailing the experimental method and results for independent review and public reference.
The objective expectation is that the resulting “truly computer generated” design will be the most aerodynamic, non-recumbent bicycle possible given modern computing technology. To ensure that the best design is manufactured Velocite will not consider the UCI limitations and will therefore deliver a bicycle aimed at triathletes and cycling enthusiasts seeking only the highest performance. The bicycle frame and rims will be made using Velocite’s advanced carbon fiber composites manufacturing and material science skills, thus ensuring that the riding performance remains at the best in class level regardless of complexities of the final design.