Streamlined body

Comparison of drag for a blunt body and a streamlined body. 

Fig. 5 Sketch ofthe completely submersed streamlined body...

The pressure drag is proportional to the frontal area and to the differ ence between the pressures acting on the front and back of the Linmersed body. Therefore, the pressure drag is usually dominant for blunt bodies, negligible for streamlined bodies such as airfoils, and zero for thin flat plates parallel to the flow. 

Marlins are large fish with elongated, bill-like snouts, fairly high dorsal fins, and a streamlined body. 

Perhaps one of the most difficult factors of littoral life is the constant pounding of waves. Life-forms have developed adaptations that help them survive the smashing, throwing, and beating action of water as it breaks against the shore. Some hold to rocks or plants so they will not wash away. Many have smooth, streamlined bodies that offer little resistance to the action of the water. Other animals cement their bodies to firm surfaces, securing themselves in place even during the worst wave action. 

There are noticeable differences between the three families, but pinnipeds share some commonalities. All members have adaptations that allow them to move with agility through the water, although they are slow and clumsy on land. Members of Pinnipedia have streamlined bodies that lack external ears... 

The cetaceans, which include whales, dolphins, and porpoises, have streamlined bodies, horizontal tail flukes, and paddle-like flippers that enable them to move quickly through the water. Layers of blubber (subcutaneous fat) insulate their bodies and act as storage places for large quantities of energy. Their noses (blowholes) are located on the tops of their heads so air can be inhaled as soon as the organism surfaces above the water. 

The functional dependence of Cd on Re ]/1 is a feature common to all streamlined bodies for which the boundary-layer analysis is valid over the complete body surface (i.e., the flow does not separate). The correlation... 

Streamlined body shape. Most of the animals, from insect larvae through fishes have a streamlined body shape, i.e. they become narrower towards the tail end. Thus, they offer a smaller resistance to the water. For example, salmon-like fish living in quickly running waters, such as trout (Salmo) or grayling (Thymallus) have cylindrical bodies with a narrow muscular tail. 

Comparison of experirnental pressures with those calculated from perfect-fluid theory for a streamlined body. [From H. Muttray, Die experimentalen Tatsachen des Widerstandes ohne Auftrieb (The experimental data of drag without lift), in Handbuch der Experimentalphysik Hydro- und Aero-Dynamik, Leipzig, 1932, p. 316 based on data by Fuhrmann.]... 

One may define a streamlined body as one for which the real-fluid streamlines cling to the body all along its length without separation normally such shapes are blunt in front and gradually taper in back. 

Will a streamlined body of revolution operating at a low Reynolds Number encounter more drag than an equivalent sphere (A sphere with diameter equal to maximum chordal length of streamlined body.)... 

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