HYDROMECHANICS

These lecture notes are the basic study material for courses in Hydromechanics, and are intended for the use by undergraduate students in mechanical engineering of the Military Technologies study program. Students are expected to have basic knowledge in mathematics and physics from previous courses.

Hydromechanics is a branch of the general mechanics. In a way similar to the mechanics of rigid bodies, hydromechanics deals with the balance of forces acting upon fluids in motion and at rest. Analyzing this motion, the knowledge of inherent laws of rigid-body mechanics is used. Fluid mechanics describes the matter by macroscopic quantities. Fluid is viewed as a continuum. The microscopic motion (the motion of molecules, atoms, ions) is neglected. The continuum mechanics assumes the properties of a continual homogenous environment in any arbitrarily small elemental volumes remain the same.

A fundamental difference between fluids and rigid bodies lies in the molecular movability of liquids and gases. In comparison with rigid bodies, the fluid is irreversibly deformed, does not have its own shape and its particles are put in motion by small forces. Otherwise, the rigid body is moved as a solid assembly of mass points (if neglect deformations).

The lecture notes give an integrated view of hydromechanics. The interpretation of problems comes from the traditional fluid mechanics using the laws of balance of forces and moments from applied loads, conservation principles of mass and energy, and the momentum theorem. Analytical solutions are difficult to obtain in many cases. Hence, it is necessary to take advantage of empirical methods. The theory of similarity is frequently used to generalize experimental results.

Illustrative problems are often followed by explanation notes, practical remarks, and examples. Notes and examples are printed in smaller size fonts.
Important passages are emphasized by italics, whereas the fundamental terms are printed in bold italics. Italic characters are also used for variables within the text. The text in italics is also used in pictures and tables captions.

The text contains the tables of physical quantities and properties of fluids to enable students to easily find necessary data for exercises and individual work.