Vena Contracta
Vena contracta is the point in a fluid stream where the diameter of the stream is the least, and fluid velocity is at its maximum, such as in the case of a stream issuing out of a nozzle (orifice). (Evangelista Torricelli, 1643). It is a place where the cross section area is minimum. The maximum contraction takes place at a section slightly downstream of the orifice, where the jet is more or less horizontal. The effect is also observed in flow from a tank into a pipe, or a sudden contraction in pipe diameter. Streamlines will converge just downstream of the diameter change, and a region of separated flow occurs from the sharp corner of the diameter change and extends past the vena contracta. Formation of vena contracta can be seen in the venturimeter. Explanation The reason for this phenomenon is that fluid streamlines cannot abruptly change direction. In the case of both the free jet and the sudden pipe diameter change, the streamlines are unable to closely follow the sharp a ...
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Hydraulic Vena Contracta 275px
Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concerns gases. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the applied engineering using the properties of fluids. In its fluid power applications, hydraulics is used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some parts of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry. The principles of hydraulics are in use naturally in the human body within the vascular system and erectile tissue. Free surface hydraulics is the branch of hydraulics dealing with free surface flow, such as occurring in rivers, canals, lakes, estuar ...
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