2.0 INTRODUCTIONThe first experiment that we conduct is comparing the flow measurement by three differentflow meters that is variable area flow meter, orifice / differential pressure flow transmitterand vortex flow meter.The function of variable area flow meter is measures fluid flow by allowing the crosssectional area of the device to vary in response to the flow, causing some measurable effectthat indicates the rate. A rotameter is an example of a variable area meter, where a weighted"float" rises in a tapered tube as the flow rate increases; the float stops rising when areabetween float and tube is large enough that the weight of the float is balanced by the drag offluid flow. Another type is a variable area orifice, where a spring-loaded tapered plunger isdeflected by flow through an orifice. The displacement can be related to the flow rate.In a meantime, Differential pressure flow meters are also known as Head type flowmeters. They are the most prevalent type of flow meters in use today. It has been projectedthat more than 50 percent of all liquid flow measurement applications make use of this typeof unit. The basic Working principle of differential pressure flow meters is based uponthe Bernoulli's Equation which states the fact that the pressure drop across the meter isdirectly proportional to the square of the flow rate. The flow rate is calculated by measuringthe pressure differential and extracting its square root. There are many types of differentialpressure flow but in this experiment we use the orifice plate to calculate the flow.Another flow measurement that we use in the experiment is vortex flow meter. Avortex flow meter works based on the principle of Karman vortex street. This principleessentially means that when an obstruction is placed in path of a flow (similar to a flagpole inthe wind), it can produce a series a vortices alternating from each side. The frequency ofalternating of these vortices is proportional to the flow rate being obstructed. The vortex typeflow meter uses a small rod called 'shredder bar' or 'bluff bar' to shred vortices from bothsides in an alternating manner.