Animals can't rotate like wheels on a car. They must move by oscillatory motion. The resulting flow of fluids are complex and create agonizing studies for biofluid students. These students often find themselves at the forefront on research in fluid dynamics of unsteady, complex viscous flows.
Often men have marveled at the dolphins and whale and at how gracefully they moved through the water. Jim Rohr, a fluid dynamicist working for the US Navy was on an evening cruise in the waters near San Diego when he saw nature doing what scientists had failed to do in the lab: reveal water motion to the naked eye. Watching the plankton bioluminesce as the boat moved by he realized that if he could measure that luminescing he could measure fuid dynamics, turbulence and laminar flow.
But how do the plakton know that the water is moving? And what forces act on animals as they swim?
The answer is mechanical strain of relative motion. Fluids flow around walls slower than they flow in the middle. As the fast molecules tug on the slow ones this creates shear stress. Since velocity is always zero, the faster the liquid, or the animal moving through it, the greater the sheer stress. This is laminar flow. But at some point laminar flow turns to turbulence. Turbulence decreases speed because it increases drag. The plakton were feeling the pull of the drag gainst their cells and luminescing.
Whales create spectacular sights as they cruise through the ocean. We have observed them as they thrust with powerful tails and direct themselves with stiff pectoral flukes. To move forward they swing their tail in vertical motions. This powerful motion can push them for hundreds of miles during migration or jettison them out of the water in amazing aerial displays. Below is an animation of an orca as it moves its tail to go forward. Notice that the front of the body is fairly rigid as a planning surface. Other whales, like the Grey Whale, are more streamline for longer journeys. The gray whale migrates from Alaska to Baja twice a year in the spring and fall.
Rohr believed that bioluminescence could solve a very large question: do whales and dolphins have frictionless skin and can we imitate it?
Laminar flow creates much less shear stress than turbulent flow at the same velocity because there is no swirling or random motion.
Image sitting on the beach one July morning. The sun is beaming down and decide to go for a swim. As you approach the water, you see a whale unusually close. You begin to get nervous as it continues to approach the shore. However, you aren’t worried because you know that they are confined to the sea. As the whale comes near you can see it clearly. Just as you think that it will turn around, the whale walks out of the ocean!
To fight is to stand up for what is right, break through the walls of what is acceptable, and to have the fire blazing in the eyes of a warrior. Throughout life society has taught humanity to form into a definite way that should not ever change, but through life there has been a small population who are immune from societies spell. The outcasts that must battle to stand up for what they believe is right. In the novels Antigone, Anthem, and in the movie Whale Rider, the main characters fight for what they believe is right by standing up to society's norms the society has deemed acceptable.
Introduction to Aerodynamics Aerodynamics is the study of the motion of fluids in the gas state and bodies in motion relative to the fluid/air. In other words, the study of aerodynamics is the study of fluid dynamics specifically relating to air or the gas state of matter. When an object travels through fluid/air there are two types of flow characteristics that happen, laminar and turbulent. Laminar flow is a smooth, steady flow over a smooth surface and it has little disturbance. Intuition would lead to the belief that this type of air flow would be desirable.
Watch a leaf flow down stream; watch its behavior within the water… Perhaps it will sit upon the surface, gently twirling along with the current, dancing around
The Marine Biology program at UCLA is geared toward students who want to specialize in the field of marine sciences. In addition to learning biology, students gain first-rate experience in such disciplines as oceonography, marine organisms, and the evolutionary processes of lif...
A hero is someone who will attempt everything in their power to help others and risk everything they have to help others. In the movie, The Whale Rider, you can clearly see all the elements of The Hero’s Journey. A young girl named Paula Apirana, is living in a small village with her grandparents. Paika’s dad, who is living in Spain, returns to see Paula and proposes that she should come live with him. She declines the offer and decided to stay with her grandparents. Paula then secretly tries to learn the important ritual, that only males are allowed to learn. Her grandpa, Paka, gets extremely angry at her until he realizes that she is the “chosen one” to perform the ritual. Paika goes through many difficult challenges, however she manages
When the Reynolds number is less than 10 .... it is considered laminar, when it is greater than 100 it is considered turbulent. The areas in between are defined as transitional and can go either way.
Jellyfish move by expanding and contracting to push the water behind them. In between each contraction and expansion is a pause so that a vortex can be created ...
Land, M.F.1965. Image formation by a concave reflector in the eye of the scallop, Pecten maximus. J. Physiol. (Lond.) 179: 138 153.
The morphology of whale sharks is mostly similar to aquatic fish species, but many specific traits help differentiate them from the rest. Whale sharks are the largest fish in the world and can reach a size of around 20 meters (Martins, C., and C. Knickle). This is often compared to the size of a school bus. The shark has a very large transverse mouth. They have 5 very large gill slits and have a larger first dorsal fin compared to the second one (Whale Shark). They have a distinctive spotted “checkerboard” pattern with stripes (Martins, C., and C. Knickle). It is not exactly known why they have this specific body marking. It is believed that the body markings act as a camouflage. The strange thing about whale sharks is that they have 300 rows of teeth that play no role in feeding (Martins, C., and C. Knickle).
Sensory systems are essential to a mammal’s survival and for providing important information concerning their internal and external environment (Hill et al., 2011). Sensory systems depend on specialized sensory receptor cells that respond to stimuli, either from the mammals’ internal or external environment (2011). One form of sensory is electroreception, which is the detection of electrical currents or fields in aquatic mammals and mechanoreceptors are specialized to respond to different types of mechanical stimuli, such as touch, taste, smell, etc. (2011). The platypus (Ornithorhynchus anatinus) exhibits electroreception with the help of mechanoreceptors to detect prey item while submerged in water.
Dinoflagellates have a pair of flagellum, transverse flagellum, that are wound up around the body and then when whipped in a wavelike fashion causes the cell to go in a spinning motion, giving it a forward propulsion. This helps the dinoflagellates keep their planktonic existence because it can help them stay at the top of the water column, making it easier for them to perform
On a more scientific note I am interested in mechanics of fluids. This interest was enforced last year when I had the opportunity to attend a lecture on fluid mechanics at P&G. At the conference I greatly expanded my knowledge regarding the physical aspect of fluids and their properties. In last year's AS course we have met a topic in this field. I will be applying ideas and knowledge gathered from last year for this investigation.
The Humpback Whale, Megaptera novaeangliae, is part of the marine mammals group. They are found in oceans all over the world, they live in open waters. Even though they are mammals, they do not live on land (Monterey Bay Aquarium). Humpback whales are known for their magical song that can travel great distances. These gentle giants are omnivores, their main diet is krill. They are mostly found near coastlines feeding on tiny shrimp-like krill, plankton and small fish. Humpbacks migrate annually from summer feeding grounds near the poles to warmer winter breeding water closer to the Equator. Humpback whales are powerful swimmers, and they use their massive tail fin, called a fluke to propel themselves through or even out of the water! Mothers and their young swim close together, often touching one another with their flippers with what appears to be gestures of affection. Even though it takes more than one year for a humpback whale to grow fully, mother whales leave them after one year (National Geographic).
The science of fluid mechanics is neither new nor biblical; however, most of the progress in this field was made in the 20th century. Therefore it is appropriate to open this text with a brief history of the discipline, with only a very few names mentioned.