University of Glasgow researchers are working to unlock the potential of bladeless wind power.
For the first time, computer simulations of bladeless wind turbines (BWTs) have pinpointed the most efficient designs for future models.
“The findings could help the renewables industry take BWTs, which are still at an early stage of research and development, from small-scale field experiments to practical forms of power generation for national electricity grids,” say the researchers.
The advantages are many: BWTs are quieter, occupy less room, and typically require less maintenance due to their simpler design.
Interestingly, BWTs are said to be safer for animals, like birds. For flying creatures, rapidly spinning standard turbine blades can appear as a blur or even be invisible due to a 'motion smear' effect. It often increases the risk of collisions.
The team’s simulations of thousands of designs revealed a 'sweet spot' where they could maximise power generation without sacrificing the structure’s strength.
Bladeless wind power
For a long time, conventional wind turbines have been our go-to for converting wind into electricity.
These turbines directly convert the wind’s kinetic energy into rotational blade motion, which then powers a generator to produce electricity.
On the other hand, the bladeless wind turbines operate on a fundamentally different principle called vortex-induced vibration (VIV).
Instead of rotating blades, BWTs are typically tall, slender, cylindrical masts, swaying like a lamppost in the breeze.
The wind’s movement generates vortices, which then make the whole structure oscillate. When this swaying motion perfectly matches the structure’s natural vibration frequency, the movement amplifies dramatically. This increased motion is then converted directly into electricity.
In this new work, the engineers used computer simulations to identify how to build future generations of BWTs for maximum efficiency.
“What this study shows for the first time is that, counterintuitively, the structure with the highest efficiency for extracting energy is not in fact the structure which gives the highest power output,” says Dr Wrik Mallik, of the University of Glasgow’s James Watt School of Engineering.
“Instead, we have identified the ideal midpoint between the design variables to maximise the ability of BWTs to generate power while maintaining their structural strength,” says Dr Malik.
Ideal design for 460 watts power
The study’s findings provide new insights into how the dimensions of the mast (like its height and width) influence both the amount of power generated and the structural integrity of bladeless wind turbines.
The findings point to an ideal design: an 80cm mast that’s 65 centimetres in diameter.
This optimal balance of power and sturdiness could safely deliver a remarkable 460 watts of power – outperforming current real-world prototypes that top out at about 100 watts.
The findings are particularly important for ensuring structural safety in winds ranging from 30km/h to 110km/h.
The researchers believe that their methodology could enable the scaling of BWTs for producing 1,000 watts or more.
“We hope that this research will help spur industry to develop new prototypes of BWT designs by clearly demonstrating the most efficient design,” says Professor Sondipon Adhikari, the corresponding author.
This concept is not entirely new. Building on the concept, BMW partnered with Aeromine Technologies last year to test bladeless wind power, with the UK’s first 'motionless' system now installed at the Oxford MINI Plant. It generates clean electricity without “visible moving parts”.
The findings were published in the journal Renewable Energy.