There are many problems of interest in the field of fluid mechanics in the real world of design that cannot be solved using the differential and integral equations only. It is often necessary to resort to experimental methods to establish relationships between the variables of interest. Since experimental studies are usually quite expensive, it is necessary to keep the required experimentation to a minimum. This is done using a technique called dimensional analysis, which is based on the notion of dimensional homogeneity—that all terms in an equation must have the same dimensions.