21. Applying the Reynolds transport theorem, one can change the reference to an arbitrary ( non-fluid ) control volume V c. 22. It is often derived from a physical basis using Darcy's law and a conservation of mass for a small control volume . 23. The control volume integration of the steady part of the equation is similar to the steady state governing equation s integration. 24. Where " n " is the normal of the surface of the control volume and " V " is the volume. 25. What interests us is the change in density of a control volume that moves along with the flow velocity, "'u " '. 26. This equation represents the balance of generation of the property ? in a Control volume and the fluxes through its cell faces. 27. The second law of thermodynamics requires that the dissipation term is always positive : viscosity cannot create energy within the control volume . 28. At steady state, a control volume can be thought of as an arbitrary volume in which the mass of the continuum remains constant. 29. As a continuum moves through the control volume, the mass entering the control volume is equal to the mass leaving the control volume . 30. As a continuum moves through the control volume, the mass entering the control volume is equal to the mass leaving the control volume.
