Introduction to unsteady flow

In many practical cases involving natural reservoirs, the surface area is not a simple mathematical function of z, but values of it may be known for various values of z. In such a case, Eq. (10.136) may be solved graphically by plotting values of S/(Qi - Q2) against simultaneous values of z. The area under such a curve to some scale is the numerical value of the integral. It may be observed that instantaneous values for Q have been expressed in the same manner as for steady flow. This is not strictly correct, as for unsteady flow the energy equation should also include an acceleration head. The introduction of such a term renders the solution much more difficult. In cases where the value of z does not vary rapidly, no appreciable error will be involved by disregarding this acceleration term. Therefore the equations will be written as for steady flow. 

Maxey MR (1993) The equation of motion for a small rigid sphere in a nonuniform or unsteady flow. ASME, FED-Vol 166, Gas-Solid Flows Middleman S (1998) An Introduction to Mass and Heat Transfer Principles of Analysis and Design. John Wiley Sons, Inc., New York Middleman S (1998) An Introduction to Fluid Dynamics Principles of Analysis and Design. John Wiley Sons, Inc., New York... 

Telionis DP (1981) Unsteady Viscous Flows. Springer-Verlag, New York Thomas NH, Auton TR, Sene K, Hunt JCR (1983) Entrapment and transport of bubbles by transient large eddies in multiphase turbulent shear flows. In Stephens HS, Stapleton CA (eds) International Conference on Physical Modelling of Multi-Phase Flows, BHRA Fluid Engineering, pp. 169-184, Cranfield Thomson WJ (2000) Introduction to transport phenomena. Prentice Hall, Upper Saddle River... 

A BRIEF INTRODUCTION TO SYNCHRONOUS TEST OF UNSTEADY FLOW AND FLOW CONDITIONS... 

The system can react to changes in the flow composition or temperature jump. A pulse method has also been introduced in heterogeneous catalysis and is used extensively. The transient flow reactor techniques that is frequently employed include the introduction of reactant as pulses, which provides unsteady state information, and step changes in reactant concentration, which provide information about the transient process from one steady state to another. The pulse method is generally less informative than the step change method in... 

---