AERONAUTICAL LECTURING NOTES

What is fluid mechanics? It is a science that deals with movement of fluids (Liquids/gas) and its interaction with solid surface. 99% of the practical flow is wall bounded. What is meant by continuum?   All matters are made up of atoms, fluids too. Atoms have some gap in between them.   Now just consider the flow over a circular cylinder of diameter d. The mean distance that an atom travels between two successive collisions is called as Mean free path (λ).   When comparing λ and d, if λ is too small than d, we can assume that the flow over the cylinder as continuum. What is no- slip condition? Consider a fluid flow over a solid surface. The layer of fluid which is attached to the solid surface sticks to the solid surface and so it has zero relative velocity with the solid surface. This is what called as no-slip condition. Due to no slip phenomenon the layer of fluid attached with the surface has zero relative velocity and the next layers are moving with ...

Define density or mass density. Density of a fluid is defined as the ratio of the mass of a fluid to its volume. Density, ρ = mass/volume (Kg/m3) ρ water = 1000 Kg/m3 Define specific weight or weight density. Specific weight or weight density of a fluid is defined as the ratio between the weight of a fluid to its volume. Specific weight, γ = weight/volume (N/m 3 ) γ = ρg γwater = 9810 N/m 3 Define specific volume. Specific volume of a fluid is defined as the volume of fluid occupied by an unit wt or unit mass of a fluid. Specific volume vs = volume/ wt = 1/γ = 1/ρg      ----- for liquids Specific volume vs = volume/ mass = 1/ρ   ----- for gases What is specific gravity? Specific Gravity = Weight of the substance/ Weight of an equal volume of   water OR Specific Gravity = Density of the substance/Density of water The same formulas are used to find the density of gases by substituting air for wat...

What is matter? Matter has following properties 1. occupies space  2. All things are made of because .  3. Matters have mass. What is mass? Mass is a measure of the quantity of matter in an object. Mass determines inertia of matter. To be more specific the mass depends purely on the intensity of atoms present in the object. Atoms have electrons,protons and Neutrons. What is weight? Whatever may be the intensity of mass (whether it is heavy or light), that mass will be attracted by bigger mass, Earth.Biggest mass in the universe is Sun. If you refer universal law of gravitation, you will find the physics behind it that is Bigger mass always attracts lesser mass. The attraction force depends upon the distance between objects in interest. When mass is attracted by some vector like gravitational force, it also becomes a vector and that vector is called as Weight.                     Weight = mass x accelera...