Theory of sonics - Alchetron, The Free Social Encyclopedia

The theory of sonics is a branch of continuum mechanics which describes the transmission of mechanical energy through vibrations. The birth of the theory of sonics can be considered the publication of the book A treatise on transmission of power by vibrations in 1918 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: mechanical including hydraulic, pneumatic and wire rope methods; and electrical methods....According to the new 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. The energy is transmitted by periodic changes of pressure and volume in the longitudinal direction and may be described as wave transmission of power, or mechanical wave transmission. – Gogu Constantinescu

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.

Book chapters

The book A treatise on transmission of power by vibrations has the following chapters:

Introductory
Elementary physical principles
Definitions
Effects of capacity, inertia, friction, and leakage on alternating currents
Waves in long pipes
Alternating in long pipes allowing for Friction
Theory of displacements – motors
Theory of resonators
High-frequency currents
Charged lines
Transformers

George Constantinescu defined his work as follow.

Theory of sonics: applications

The Constantinesco synchronization gear, used on military aircraft in order to allow them to target opponents without damaging their own propellers.

Automatic gear

Sonic Drilling, was one of the first applications developed by Constantinescu. A sonic drill head works by sending high frequency resonant vibrations down the drill string to the drill bit, while the operator controls these frequencies to suit the specific conditions of the soil/rock geology.

Torque Converter. A mechanical application of sonic theory on the transmission of power by vibrations. Power is transmitted from the engine to the output shaft through a system of oscillating levers and inertias.

Sonic Engine

Elementary physical principles

If v is the velocity of which waves travel along the pipe, and n the number of the revolutions of the crank a
The wavelength λ is =v/n
Assuming that the pipe is finite and closed at the point r situated at a distance which is multiple of λ, and considering that the piston is smaller than wavelength, at r the wave compression is stopped and reflected, the reflected wave traveling back along the pipe.

Alternating fluid currents

Considering any flow or pipes,if:

and

then we have:

Assuming that the fluid current is produced by a piston having a simple harmonic movement, in a piston cylinder having a section Ω. If we have:

Then:

Where:

If T= period of a complete alternation (one revolution of the crank) then:

The effective current can be defined by the equation:

The stoke volume δ will be given by the relation:

Alternating pressures

The alternating pressures are very similar with alternating currents in electricity. In a pipe were the currents are flowing, we will have:

Considering the above formulas:

If p₁ is the pressure at an arbitrary point and p₂ pressure in another arbitrary point:

The effective hydromotive force will be: H e f f = H 2

Friction

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:

Using experiments R may be calculated from formula:

Where:

γ is the density of the liquid in kg per cm.³

l is length of the pipe in cm.

g gravitational acceleration in cm. per sec.²

ω section of the pipe in square centimeters.

v_eff the effective velocity

d internal diameter of the pipe in centimeters.

for water ϵ = 0.02 + 0.18 v e f f d this is an approximation made by experiments.

h is instantaneous hydromotive force

If we introduce ϵ in the formula, we get:

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:

Capacity and condensers

Definition: 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.

References

Theory of sonics Wikipedia

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