Category: Advance Concept Mechanical Eng

Let h = Height of liquid in tube, σ = Surface tension of liquid, and θ = Angle of contact between liquid and glass tube.

Example 9.2: The surface tension of water in contact with air at ambient temperature is 0.10 N/m. The pressure inside the water droplet is 0.03 N/cm2 greater than the outside pressure. Calculate the diameter of water droplet. Solution: Example 9.3: Find the surface tension in a soap bubble of 50 mm diameter when the inside pressure is 4…

Let σ be the surface tension of liquid, p be the pressure intensity inside the droplets and d be the diameter of droplets. Tensile force due to surface tension acting around the circumference of the liquid droplets will be equal to pressure force on the projected area.

Surface tension is the tendency of the surface of a liquid to behave like a stretched elastic membrane. There is a natural tendency for liquids to minimize their surface area. The obvious case is that of a liquid droplet on a horizontal surface that is not wetted by the liquid—mercury on glass or water on…

An ideal fluid has zero viscosity. Shear force is not involved in its deformation. An ideal fluid must be incompressible. Shear stress is zero irrespective of the value of ∂u/∂y. Bernoulli equation can be used to analyse the flow. Real fluids having viscosity are divided into two categories, namely, Newtonian and non-Newtonian fluids. In Newtonian fluids a linear…

Viscosity, μ is a property of fluid which offers resistance to sheer deformation. Different fluids deform at different rates under the same shear stress. Fluid with a high viscosity, such as lubricant oil deforms more slowly than fluid with a low viscosity such as water. In any fluid flow, layers move at different velocities and the fluid’s…

σ is defined as the ratio of mass density of a fluid to some standard mass density. For solids and liquids this standard mass density is the maximum mass density for water (which occurs at 4°C) at atmospheric pressure.

ω (sometimes γ, and sometimes known as specific gravity) is defined as the weight per unit volume or the force exerted by gravity, g, upon a unit volume of the substance. The relationship between g and ω can be determined by Newton’s second law, since weight per unit volume = Mass per unit volume × g. S.I. unit of fluid is Newton per…

ρ, is defined as the mass of substance per unit volume. S.I. unit of mass density is kilograms per cubic metre, kg/m3, and dimensions is ML−3.

The fluid density is the quantity of fluid contained in its unit volume. It can be expressed in three different ways: mass density, specific weight, and relative density.