CFD/FEM Analysis of existing and extinc animals

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Nicknick

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Whenever I see an animation of flying or swimming extinct animals they look wrong to me, unlike most simulated walking animals which look pretty natural. Palaeontologist are discussing animal behaviour and flight techniques based on existing animals and muscle distribution, but rarely on CFD. I know it would be very complex to combine a FEM model for the skeleton and the muscles with a soft, morphing outer geometry and CFD Simulation, but it would be a nice scientific project to create a self-optimizing model of a Ptetosaur or Meganeura and see, how they flew. An insect like Meganeure would be a good starting point, because it will be simpler for modelling because of its rigid body elements.

I’m not deep enough into this topic, but maybe that idea inspires someone to start a research project (even with my taxpayer money) for this.
 
I think expected difficulties are
1. considering "flexible membrane" causing fluid-structure interactions for low-Reynolds number condition
2. hard to find appropriate material properties
3. assumption of wing-motion for effective lift

w/ these information, someone could start
 
As I said, it's not easy, but not impossible, ski jumping is allready beeing analyst and material properties can be estimated from living animals. There have been FEM/mulibody simulations of running T-Rexes, so the boundary conditions can be defined within a reasonable tolerance. The wing motion would be the result of an optimation process, not of input data.
 
The was something in phys.org about swimming inducing useful vortices….
 
Interesting idea. We can validate the modelling against living birds or insects before trying something extinct. Not sure anyone but us geeks care about the popular science animations though.
 
Some movie makers really like to come close to reality, as well as parts of the gaming industry. It would be nice if they spend a fraction of their budget to improve a movie or video game.
 
In this type of simulation, the mistake is sometimes made of focusing exclusively on the animal and ignoring the environment in which it had evolved. Dinosaurs are usually depicted on illustrations walking in a volcanic landscape or in a forest, basically a green background without specifying what type of plants and their content in nutrients, alkaloids and tannins. The flying animals of times past are reconstructed without considering the oxygen content of the atmosphere or how they affected the climate and humidity of the air to their wings or what mechanisms the animal had adopted to improve its maneuverability, its resistance in flight, its navigation systems, its predators and its prey. What food content his meals had, compared to his weight and how often he had to feed so as not to fly too much load. Personally what interests me most is what can be found out about navigation systems: magnetite particles in the inner ear, sun angle, infrared or ultraviolet vision ability and perhaps other completely unknown senses that developed only once to facilitate the survival of a group and were lost afterwards.
I include illustrations on the mechanism of flight with membranous wings made by the Catalan illustrator Vicente Segrelles, for the comic book series "El Mercenario".
 

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Thanks for the pics, he was very likely inspired by Pterosaurs.

We will never know exactly what the world looked like 60 million years ago, but we might get a little closer. At least, the gravity and air density hasn’t changed a lot. The air density is not much affected by the oxygen or humidity content. It is difficult to find an upper limit for speed and range of extinct flying animals, but we could find a solution for flying/swimming as energy effective as possible. It is very likely, that e.g. large Pterosaurs were flying energy optimized like large birds, for maximum range and low energy consumption. Another example are the Mosasaurs with their four fins, did they swim like a Coelacanth? I believe by trying to find the most energy effective propulsion method, we could find out how they really moved trough the water and the sky.

For the maximum performance and animal behavior we would need much more information, like the food, number of predators and so on.

Magnetic particles, like in birds, could sustain through times, I wouldn’t be to surprised if we find some of them in fossil records.
 
Nicknick said:
Another example are the Mosasaurs with their four fins, did they swim like a Coelacanth?
Click to expand...
The mosasaurs, I gather, swam mainly using their tails for propulsion and their flippers for steering. They're more like modern cetaceans, except the strokes are side-to-side rather than up and down.

The plesiosaurs were more complicated. Here are some studies and I think that like coelacanths, they swam more like land quadrupeds walk, with various gaits depending on speed, but that's just my intuition - the hydrodynamic analyses have only been of the interaction between the fore and aft flippers, not of the whole system of four. We have few examples of swimming quadrupeds except coelacanths - penguins 'fly' using just their forelimbs and turtles really only use their hind limbs for steering when swimming, so I don't think that they're a useful model.


View: https://www.youtube.com/watch?v=fWWUKV_-_Wc&ab_channel=LukeMuscutt


www.newscientist.com

Plesiosaur X-ray helps create swimming robot mimic

The motion of an extinct marine reptile is being reconstructed thanks to a well-preserved fossil, computer simulations and a robotic replica
www.newscientist.com www.newscientist.com

Technically, the last is paywalled but if you stop the download before it's completely loaded, you can bypass it. It takes practice or at least several attempts.
 
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As an example of convergent evolution, mosasaurs in their later stages were evolving to forms similar to modern whales. Compare this late mosasaur, Tylosaurus, with an early whale, Basilosaurus. Some of the best mosasaur fossils have shown impressions of their fins and tails, so the art below is actually pretty accurate. The tails are long and muscular, which is not the case for coelacanths or plesiosaurs, so ti was their tails, not their fins that were the means for their propulsion. The strokes of the tails for the mosasaurs, like the ichthyosaurs, are side-to-side rather than up and down as they are for cetaceans.
 

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Great links, made my day!

I mixed the mosasaurs with the plesiosaurs, but you gave me the right answer anyway. It reminds me a bit of counter rotating propellers were the aft prop is counteracting the swirl from the front prop. If I got it right, the aft fin was acting counterwise the flow (up or down) from the front fin. The phase betwen these fins was depending from the frequency, speed and distance and not simply 180° degree offset. Both sides would have acted simultaniously.

You might know this series on youtube:

View: https://www.youtube.com/watch?v=scAp-fncp64&ab_channel=PBSEons


There is a new idea about how these giant pterosaurs took off, which was totally diferent from everything we know about birds or bats
 
I love the fact that one's nicknamed Dracula.


At the time, the region was an archipelago. Conventional wisdom is that a predator would be small to be able to inhabit a single island but the giant pterosaurs' habitat was a sea dotted with islands, not single islands. Just put skin on this skeleton and it couldn't be less terrifying.
 

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I knew about Northtorpi pterosaur, nice name, hopefully there will be a Junkeri too in future...

I think, it is quite logic, that a skinny flying animal with a large surface have feathers, otherwise it would loose very much energy to the air during flight. Despite the hugh size, the Quetzalcoatlus northropi hat a low weight of about 150 kg, so it would easily freeze to death even at moderate temperature without any isolation.

There is one thing i dislike about the trailer, for good reasons, it is very unlikely that dynosaurs sounded like lions, no bird or reptile makes noises which are anything like that.
 
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Finding a pterosaur must be an absolute jackpot for archaeologist, they are very rare, due to their lightweight bone design. I haven’t fully understood the text (I never learned Latin and my English is only moderate…) but the graphics are clear. I wonder, if a slightly pressurized bone would have been possible to further reduce the risk of buckling (the Goodyear Inflatoplane just crossed my mind…).

Interestingly they used the CT just accidentally, many discoveries were based on luck and awareness.

It’s a bit like the story of Mary Schweitzer who found the first organic material in dinosaur bones

Mary Higby Schweitzer - Wikipedia

en.wikipedia.org en.wikipedia.org

About the shark skins: I never understood or found a plausible explanation of how these skin really works.

I hope no one will start adding dolphin skin in anti-aging creams…
 

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