Q. Briefly explain Model scale design?

Knowledge of dynamic similarity conditions enables evaluation of model scales. Almost alI the problems related to river hydraulics are about gravity flow and hence required to follow the condition of equality of Froude Number. In evolving model scales for such problems it is logical to classify models of different types and consider them separately. First broad classification is according to nature of boundary- rigid boundary and mobile boundary models. Next grouping in each category can be according to geometry - whether geometricalIy similar or dissimilar on account of vertical exaggeration.