Research and Development
During the research and development stage of the design process I used both qualitative, on-the-water testing and fluid dynamics software to prove the effectiveness of my concepts. I also conducted research into the type of training that this product is used for (across multiple sports) and what requirements a market-ready product would need to make it an effective training tool. This page will detail my research and how I used it in the design and manufacture of OHM products.
Canoe Slalom is a minority sport (1) , so there is very little academic research into methods of training such as the aforementioned resistance training. However , I wanted human biology based secondary research to dovetail my engineering and design based primary research so I started to look at other sports that use similar methods. In swimming, parachutes have been developed to add resistance to the body and facilitate the use of conditioning exercises such as post activation potentiation (PAP). This is described as ‘an increase in muscle isometric twitch and low frequency force’ (2), and is done by increasing the load to make the muscles work harder in training in order to condition the muscles to work faster and more efficiently when racing. This is essentially the same method that athletes use in canoeing, and has been proven through testing by high level American swimmers.
Three groups tested this method in slightly different ways to test the effectiveness on performance. The first group took 30 college athletes (a combination of men and women) and compared using and not using PAP over a 100m distance with a large rest (6minutes). The PAP was done in the warm up using a power tower. The PAP trials recorded an overage of 0.54s faster over 100m compared to without. There was also no difference between the men and the women , so PAP worked equally well for both.
The second study used a group of 9 international level sprinters. The swimmers jumped from the blocks and sprinted from to the 15m line. Both power off the blocks, and vertical height increased with the PAP stimulus. The third study took nationally ranked swimmers and compared four different warm ups- regular swim warm up, upper body PAP , lower body PAP and full body PAP. The males performed better with the PAP routines , but the regular swim warm up outperformed the PAP methods. Overall this method shows that this type of training is effective in some aspects of swimming performance, and so will also help in canoe slalom training. This research provides evidence for the usefulness of drag-resistance training, and facilitates the development of a product such as the one I am developing.
In addition to this secondary research I arranged a meeting with
Julian Fletcher, a programme manager at Rolls Royce. Recently he has been
working on the Triton project, which broke the world record for the furthest
distance on water by a human powered vehicle during a 12 hour period. The team
broke this record through careful development of a design that aimed to reduce
drag to an absolute minimum, and we spoke about how I could use his ideas in
reverse to increase the drag for training purposes. This primary research was vital in the final
development of my product, because he suggested ways to test my designs using
both a computer simulation (with the Flow Simulation on Solidworks),
and also methods to determine drag practically. We discussed the use of practical testing, the
most
suitable
being
a qualitative test whereby a range users take
the product and test it on the water, judging the drag by how it feels compared
to other designs, and without any device fitted. This complemented the data
producing CFD (Computational fluid dynamics) software testing I was also doing.
Following my research and development into the design of the device, I started to experiment with cube shaped objects. Using the NASA data I had used , I knew that this was one of the shapes that induced the most drag, and having experimented with a flat plate (the design that induces the most drag) had decided that it would be difficult to implement logistically because it was lifting up to a flat position when the boat moved forwards due to the drag force. Also the amount of drag it created would potentially have caused injury due to the resistive force that it induced.
I wanted to try using a cube shaped design because it is identical in all directions, meaning that the product will not change it’s position when force is applied. I did some sketches, and then modeled the best design on solidworks. I used the ‘fins’ to increase the contact surface area with the drag force. The formula for drag force is (Force = (Drag Coefficient * density of the fluid * velocity ^2 * area of frontal face)/2), so force is directly proportional to area. The design was inspired by some parts in computers, which have similar fins to increase the surface area , allowing them to cool down quicker.
The most common design solution I had found during research was tennis balls on a bungee, so I used this as my control variable. When I ran my design (made up of 3 cubes) through the programme, it gave me a drag coefficient that was 2x greater than that of 3 tennis balls, with a 6% error margin.
(Above) - An image of the model I used to calculate the drag coefficient of my design.
(Above) The results from the CFD calculation of the drag coefficient of my design.The value of 0.119502 is greater than that of my control, proving the effectiveness of my design.
Following this, I manufactured a prototype using silicone moulding techniques. I then used this in my training for 6 months before asking others to test it. Following positive feedback, I decided to manufacture, advertise and sell the product to other athletes.
References
1-https://www.telegraph.co.uk/technology/3357238/Top-10-links-for-minority-sports-and-the-olympics.html
2- https://bjsm.bmj.com/content/38/4/386
3 – Finding the drag coefficient with CFD https://www.youtube.com/watch?v=_VjAka70C1w&list=PLtH1ZG5mk1zNzz5HO9UcuuYzGIHBSQOIk&index=9