George (Gogu) Constantinescu (October 4, – December 11, ) was a Romanian scientist and engineer, often considered to be one of. Abstract: George (Gogu) Constantinescu (October 4, – December 11,. ) was a Romanian scientist and engineer, often considered to. Gogu Constantinescu had innovative ideas in the field of reinforced concrete and of the mathematical machinery. His technical work includes construction after.
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The theory of sonics is a branch constanfinescu continuum mechanics which describes the transmission of mechanical energy through vibrations. The birth of the theory of sonics  can be considered the constantjnescu of the book A treatise on transmission of power by vibrations in by the Romanian scientist Gogu Constantinescu.
ONE of the fundamental problems of mechanical engineering is that of transmitting energy found in nature, after suitable transformation, to some point at which can be made available for performing useful work. The methods of transmitting power known and practised by engineers are broadly included in two classes: According to the cpnstantinescu system, energy is transmitted from one point to another, which may be at a considerable distance, by means of impressed variations of pressure or tension producing longitudinal vibrations in solid, liquid or gaseous columns.
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The energy is transmitted by periodic changes of constxntinescu and volume in the longitudinal direction and may be described as wave transmission of power, or mechanical wave transmission. Later on the theory was expanded in electro-sonic, hydro-sonic, sonostereo-sonic and thermo-sonic. The theory was the first chapter of compressible flow applications and has stated for the first time the mathematical theory of compressible fluid, and was considered a branch of continuum mechanics.
The laws discovered by Constantinescu, used in sonicity are the same with the laws used in electricity. Suppose the crank a to be rotating uniformly, causing the piston b to reciprocate in the pipe c, which is full of liquid.
At each in stroke of the piston a zone of high pressure is formed, and these zones, shown by shading, travel along the pipe away from the piston; between every pair of high pressures zones is a zone of light pressure shown in the picture.
The pressure at any point in the pipe will go through a series of values from a maximum to a minimum. If the crank continues rotation at uniform speed, a zone of maximum pressure will start from the piston at the same time the reflected wave came to the piston, as a result the maximum pressure will double.
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At next rotation the amplitude is increased, and so on, till the pipe burst. If more energy is produced by piston b then is taken by piston m the energy will be reflected by piston m in pipe, and the energy will accumulate till the pipe burst.
If we have a large volume vessel d, compared with the stroke volume of piston b, the capacity d constantinesc act as a spring taking out the energy of direct or reflected waves at high pressure, and giving back energy when pressure falls.
The mean pressure in d and in the pipe will be the same. The result of reflected waves will be a stationary constantinesc in pipe with no increase of energy, and the pressure in the pipe will never exceed the pressure limit. Waves are transmitted by a reciprocating piston along the pipe eeee. The pipe is closed at p, a distance of one complete wavelength. There are branches at one-half, three-quarters and one full wavelength distances.
If p is open and d is open, the motor l will rotate synchronous with motor a. The maximum and minimum points do not move along the pipe, and no energy flows from generator a. If valve b is open, the motor m is able to take the energy from the line, the stationary half-wave between a and b being replaced by a traveling wave; between gogy and p a stationary wave will persist.
If only valve c is open, since at this point the variation of pressure is always zero, no energy can be taken out by the motor n, and the stationary wave will persist. If the motor is connected in an intermediary constantinesck, part of the energy will be taken out by the motor while the stationary wave will persist at reduced amplitude.
If the motor l is not capable of consuming all the energy of the generator a, then there will be a traveling wave a and a stationary wave. Therefore, there will be no point in the pipe where the pressure variation will be zero, and consequently, a motor connected at any point of the pipe will be able to use a portion of generated energy.
The alternating pressures are very similar with alternating currents in electricity. In a pipe constaninescu the currents are flowing, we will have:. If p 1 is the pressure at an arbitrary point and p 2 pressure in another arbitrary point:. The effective hydromotive force will be: In alternating current flowing a pipe the friction appear at the surface of the pipe and also in liquid itself. Therefore, the relation between the hydromotive and current can be written:.
For pipes with greater diameter greater velocity can be achieve for same value of k. The loss of power due to friction is calculated with:. Hydraulic condensers are appliances for making alterations in value of fluid currents, pressures or phases of alternating fluid currents. The apparatus usually consists of a mobile solid body, which is dividing the liquid column, and fixed elastically in a middle position, in such way that it follows the movements of the liquid column.
The principal function of hydraulic condensers is to counteract inertia effects due to moving masses. If d is the diameter of conztantinescu spring wire and the D the mean diameter of the spring.
The above equations are used in order to calculate the springs required for a condenser of a given capacity required to work at a given maximum stress.
From Wikipedia, the free encyclopedia. This glgu includes a list of referencesbut its sources remain unclear because it has insufficient inline citations. Please help to improve constantijescu article by introducing more precise citations. March Learn how and when to remove this template message. A Treatise on Transmission of Power by Vibrations.
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Figure V Waves are transmitted by a reciprocating piston along the pipe eeee.
Simple Harmonic The principal function of hydraulic condensers is to counteract inertia effects due to moving masses. If the piston is held by a spring at any given moment: In the condenser we will have: G the coefficient of transverse elasticity of the metal.