The current F1 projects I’m working on right now are highly confidential so I can’t really share these details with you at the moment and in order that I satisfy your hunger for all things technical and wizardy I thought I’d try to explain some detail behind this regularly discussed topic of ‘How does a bumblebee defy the laws of aerodynamics?’
Based upon its mass, its wing size, wing beats per second, it clearly does defy the natural laws of aerodynamics – but nature has a habit of doing that, no?
In 1934, French entomologist Antoine Magnan (1881-1938) included the following passage in the introduction to his book Le Vol des Insectes:
Tout d’abord poussé par ce qui se fait en aviation, j’ai appliqué aux insectes les lois de la résistance de l’air, et je suis arrivé avec M. Sainte-Laguë à cette conclusion que leur vol est impossible.
This translates to:
First prompted by what is done in aviation, I applied the laws of air resistance to insects, and I arrived, with Mr. Sainte-Laguë, at this conclusion that their flight is impossible.
Magnan refers to his assistant André Sainte-Laguë, a mathematician.
Now in 1934, they may have had great fashion, Hercule Poirot and infamous gangsters – in fact this week in 1934 Bonnie & Clyde were shot in Louisiana (no idea why I know this snippet) – but they didn’t have Computational Fluid Dynamics or powerful computers to run millions of complex equations to satisfy such questions, as I have today.
These developments in computer chips and indeed in science have allowed us to delve further into this $64,000 question that has been wrestled with for many years.
It is commonly thought, prior to any computational proof being carried out, that calculations suggested that bumblebees were unable to fly due to some simplified ‘linear’ treatment of oscillating aerofoil’s. The method kind of assumes minute amplitude oscillations but without any flow separation. This would ignore the effect of dynamic stall, which is a large vortex over the wing induced by the airflow separation, that briefly produces several times the lift of the aerofoil in regular flight.
Further to this, considerably more sophisticated aerodynamic research illustrates that flight is achieved by the bumblebee because its wings experience this ‘dynamic stall’ throughout every wing oscillation cycle!
But even this does not really complete the full picture and cannot account for why the bumblebee can actually fly!
So, how do bumblebees achieve sustained flight, and maintain this flight with a heavy cargo (pollen collected during its 9 to 5)?
Again, nature (as I described in my last post ) has already created something that humans take credit for….. the turbocharger or jet engine!
Yes…… Bumblebees have natures very own turbocharger strategically positioned between the hinges of its wing and its body. These simple ‘tubes’ employ Bernoulli’s Equation…
Which is also satisfying Newton’s 2nd Law -
The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
In simple terms, and in the case of the bee, imagine it has a funnel under its arm (wing) pit, with the large diameter it the front and reducing to the small diameter at the back. This funnel is a primitive, nature’s version, of a turbocharger/jet engine and as the bee beats its wings this flexible ‘funnel’ squirts air from the large diameter through to the small diameter – and as its satisfies Newton’s Second Law of Motion and Bernoulli’s equation stated above – the air being squirted through said funnel increases in velocity relative to the reduction in pressure and therefore providing additional thrust – much like a jet engine.
Bernoulli’s Principle (the pressure in a fluid decreases as the fluid’s velocity increases) states that as a fluid travels from a large (high pressure) diameter pipe to a small (low pressure) diameter pipe the same amount, or volume of fluid needs to pass through this reduced cross-sectional area in the same amount of time and therefore has to speed up – in the case of the bee, additional thrust with each beat of its wing.
Below is the formula to represent the above illustration…
I am unaware of a bumblebee being physically tested in a wind-tunnel and would expect the bee to object to being strapped to a rigid strut in the face of a very large fan – in lieu of this virtual simulations have been carried out to verify the above.
So now you know how a bumblebee can fly – and when you’re in the garden and one fly’s past, try to grasp the complex physics that is actually taking place, evolved by nature!
It’s fundamentally not that complicated just the physics to understand it and again nature, the perfect mathematician and engineer, has solved the impossible.
Right. Lunch…Honey Roast Ham on wholemeal I think!