The momentum transfer is governed by the conservation of momentum equation, which states that the rate of change of momentum is equal to the sum of the forces acting on the fluid element. The conservation of momentum equation is expressed as:

Mass transfer refers to the transfer of mass from one phase to another due to the concentration gradient. There are two types of mass transfer: diffusion and convection. Diffusion occurs due to the random motion of molecules, while convection occurs due to the fluid motion.

The turbulence is governed by the Navier-Stokes equations, which describe the motion of a fluid. However, the Navier-Stokes equations are nonlinear and difficult to solve for turbulent flows.

The viscosity of a fluid is a measure of its resistance to flow. The thermal conductivity of a fluid is a measure of its ability to conduct heat. The diffusivity of a fluid is a measure of its ability to transport mass.

The turbulence models, such as the k-ε model and the k-ω model, are used to simulate the turbulent flows. These models describe the turbulent flow in terms of the turbulent kinetic energy and the dissipation rate.

Heat transfer refers to the transfer of thermal energy from one body to another due to the temperature gradient. There are three modes of heat transfer: conduction, convection, and radiation. Conduction occurs due to the vibration of molecules, convection occurs due to the fluid motion, and radiation occurs due to the electromagnetic waves.