In Korea, AVIIAV has conducted the first wind tunnel test on wheels. While several domestic makers have conducted similar experiments, there were limitations in deriving and comparing actual data. We at AVIIAV have manufactured special jigs and rollers to measure wheel drag according to yaw angle, conduct comparative tests, and measure drag when actual riders use the wheels, including on finished vehicles, to use in product development.
The wind tunnel was conducted at the KOCED Large Wind Tunnel Experiment Center located at Jeonbuk National University. The KOCED Wind Tunnel Experiment Center is a nationally accredited research facility that specializes in conducting wind tunnel experiments related to various buildings and mobility. This experiment was conducted by KOCED Senior Researcher Seungho Lee (Ph.D) and Researcher Byeongcheol Won.
In particular, KOCED's facility is a research laboratory that has more diverse and sensitive measurement sensors and a wider and deeper wind tunnel than other overseas wind tunnels, minimizing vortices generated on the wall and generating uniform wind speeds.
Also, in order to create a condition similar to an actual driving environment rather than a stationary wheel, a motor-rotating roller was created and the wheel was rolled on it to measure the actual drag caused by the rotation of the wheel. In addition, in order to minimize the influence of equipment such as rollers, a special windshield was installed and fixed to the floor to increase the accuracy of the measurement.
In this wind tunnel test, we prepared 4 types of our own wheels and 3 types of wheels from other companies, and measured the drag for each wheel from 0 to 20 degrees. The data was measured 1,000 times per second for approximately 1 minute and the average value was calculated.
The wind speed is 11.11 m/s (approximately 40 km/h), and the wheel rotation speed is also set to 309.3 rpm, the same as the wind speed.
We measured the force applied to the wheel when there is no air resistance by measuring for 30 seconds in still conditions, and this was used to compensate for the drag when there is actual wind.
We measured not only the individual wheels but also the drag the bike receives. Depending on the yaw angle, the force received by the bike showed different values than when the wheels were measured individually. These values will be used in the development of future products.
In addition, this wind tunnel test used a smoke generator to see how the actual airflow acting on the bike changes. It was an important experiment to visualize the airflow rather than just the data values, so that we could understand the airflow according to the yaw angle and posture.
In this way, AVIIAV is putting a lot of effort into producing aerodynamically improved and verified wheels. From the CFD analysis using Ansys, which AVIIAV first introduced, to the indoor velodrome test conducted recently, and this wind tunnel test, it was a good opportunity to prove the aerodynamic performance of AVIIAV products.
We are also releasing this wind tunnel data to provide the measured data in the form of a white paper for objective evaluation and verification of our AVIIAV products. You can download it from the link below.
Please look forward to AVIIAVb’s continued challenges.
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