Meet Prof. Mehmet Pakdemirli of Celal Bayar University, an expert in applied mathematics in the science of motion, who studies mechanical vibrations and fluid mechanics. Part 3/5
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The Dynamics of Existence Part 3/5 Male: According to Dr. Pakdemirli, we can observe the issue of pressures differential in the Bernoulli’s Principle in this simple act of breathing. When we inhale, the fluid velocity is higher inside the nose and the pressure it creates could cause the wall of the nose to collapse causing permanent damage if it were a rigid structure. Instead, the wall of the nose is created using cartilage which has elastic properties allowing it to deform and reform but not break. This same principle is also at work in the ear allowing a more flexible response to changes in air pressure for example when we sleep or experience a rapid descent in an elevator. He goes on to point out that another important issue is friction which is called “drag force” in fluid mechanics. Reducing the drag force of fluid moving inside a rigid body is a streamlining of the paths of fluids or particles moving within fluids. There are many different techniques of streamlining or reducing drag values that are observable in nature. All fast moving fish, birds, and mammals are streamlined without any of abrupt changes in body shape that might increase drag. The dolphin has very good drag values and is a good example of a streamline shape. Dr. Pakdemirli: Another point is the flight itself. In airplanes we need regular float motion. We call it laminar flow. And laminar flow—the flow particles—the flow layers move in laminars so they are smooth layers. In turbulent flow, there are erotic parts of flows. The flow particles in this small scale collapse with each other. They are from this— they are called light and this is a very irregular motion. So, turbulence is not good for engineering structures like the planes. We want to maintain laminar flow as much as we can. However, turbulence also increases the friction forces. But in insect flight, turbulence is the main issue. The insects, they use turbulence to perform better—to fly better so they get benefits from the Eddies over their wings and some of the Eddies—by the -, they get at least force. So, they are designed better compared to our engineering structures. Male: Another important issue in engineering is strength of materials. Machines and mechanisms must be built to safely withstand the load conditions required of them. The same is true for living organisms which must be able to function safely during their life span. In the opinion of Dr. Pakdemirli, the creation of living organism is usually superior to engineer products. A comparison of a building to human being for instance reveals that 60 to 70 percent of the weight of a building is in its skeleton or framework where as it is only around 15 percent of the weight of a human. Having a light structure using minimum materials creates a better performance. In a similar examination of material structures, Dr. Pakdemirili explains that hollow pipes are stronger than solid pipes while also being lighter. Dr. Pakdemirli: The inner to outer ratio of the pipes is an important issue. And as we cut the bones, we see that the inside of the bones of all mammals including humans are hollow so this is increases the strength but you should have an optimum ratio of the inner to outer ready and this optimum ratio between 0.4 to 0.7. When investigated, this mathematical outcome is very right in living gracious—

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