Streamlined shape
The streamlined shape is the ideal shape of a body, which is characterized by the lowest possible flow resistance to the medium flowing around it , mostly air or water . A quantitative measure of streamlining is the drag coefficient ; In a first approximation, this is only dependent on the shape, not the size of the body in the flow. The lower its value, the more streamlined the body. The shape of the streamline can be read qualitatively from a smooth, largely vortex- free course of the streamlines , which can be made visible in numerical simulations or wind tunnel experiments.
Vehicles and aircraft, ships and submarines are usually designed according to the rules of fluid dynamics in order to be as streamlined as possible.
Nature also shows a special streamline shape in some animals. Fish, whales and penguins in particular are particularly streamlined. Birds adapt particularly well to the rules of aerodynamics.
The aim, both in technology and in nature, is to move through a medium with as little energy as possible.
The term streamlined shape was coined at the beginning of the 20th century in the course of the ever increasing speeds of motorized air and land vehicles and the emerging problem of air resistance. Last but not least, airships , especially zeppelins , became a synonym for streamlined form and technical progress, although the zeppelin competitor Schütte-Lanz had introduced this form for airships. Many scientific aerodynamic principles date from this time.
Famous are z. B. the streamlined shapes of older cars, which are represented by particularly curved lines. Since the streamline shape was mostly limited to hints and hardly any research was carried out in the wind tunnel, the actual drag coefficient was very poor. Low-flow vehicles such as Edmund Rumpler's drop car from autumn 1921 with a rating of only 0.28 and the Chrysler Airflow from 1934 failed on the market. Most successful in Europe in the thirties were the Tatra 77 and its successors. Research by Paul Jaray and Wunibald Kamm received little attention and was later interrupted by World War II.
The streamlined locomotives are also worth mentioning . An example of this is z. B. the German DR series 03.10 or the DR series 05 (world record 1935 with 200.4 km / h), the streamlined versions of the US Hudson locomotives and the English locomotive Mallard (the world record for steam locomotives that still exists today with 201, 2 km / h). At the same time, entire streamlined trains were developed, starting with the diesel-electric Flying Hamburger and the steam-powered Henschel-Wegmann train . Since the 1930s , these trains have provided the premium service for rail transport. They also formed the basis for today's high-speed trains .
Significant pioneers of only briefly as streamlining designated streamlined designs were Raymond Loewy , Norman Bel Geddes , Henry Dreyfuss and Otto Kuhler .