Mechanical Engineering - Hydraulics and Fluid Mechanics - Discussion

No, The very fact that E, (C, N or G), K and 1/m are called elastic constants and their values are determined experimentally. When E and 1/m are constants, how can K vary?

Well said @Kishan.

It's become harder and harder to compress fluid that's why when we increase pressure bulk modulus also increase.

For material it is constant.

But for fluids, especially gas.
Bulk modulus = p(isothermal).
= Y p (adiabatic).
Y~ heat capacity ratio.
Here it mentioned fluids so ans is increase with pressure.

Bulk modulus of liquid is the ratio of Inertia force to elastic force, which is also called Mach no or Cauchy's no.

So, if pressure increases then elasticity will be less, Then obviously Bulk modulus will be more or increase.

The concept of the bulk modulus is mainly applied to liquids, since for gases the compressibility is so great that the value of K is not a constant.

Strictly speaking, the bulk modulus is a thermodynamic quantity, and in order to specify a bulk modulus it is necessary to specify how the temperature varies during compression: constant-temperature (isothermal K_T), constant-entropy (isentropic K_S) , and other variations are possible. Such distinctions are especially relevant for gases.

For an ideal gas, the isentropic bulk modulus K_S is given by K_S = γ, p.

And the isothermal bulk modulus K_T is given by K_T = p.

Where,
γ is the heat capacity ratio.
P is the pressure.

When the gas is not ideal, these equations give only an approximation of the bulk modulus. In a fluid, the bulk modulus K and the density ρ determine the speed of sound c (pressure waves), according to the Newton-Laplace formula.

C = sqrt{K/ρ}.

In solids, K_S and K_T have very similar values. Solids can also sustain transverse waves: For these materials one additional elastic modulus, for example the shear modulus, is needed to determine wave speeds.

It should remain same since Bulk modulus is a property.

Bulk modulus is a constant quantity. As we change the pressure, there will be corresponding change in volume as well.

Change in pressure/(- Change in volumetric strain).