Relationship between a model and Similitude

Relationship mingled with a model and Similitude For a model, similitude is achieved when interrogation conditions ar created such that the test results ar applicable to the sincere design. There be some criteria that are demand to achieve similitude 1 . Geometric relation The model is the comparable shape as the applications programme (they are usually scaled). 2. Kinematic similarity Fluid emanate of both the model and real application must undergo similar epoch ranges of change motions. (Fluid streamlines are similar). 3.Dynamic similarity Ratios of all forces acting on orresponding gas particles and boundary surfaces in the two systems are constant.The application is analyzed in drift to satisfy the conditions 1 . All parameters required to describe the system are de limitine employ principles from continuum mechanics. 2. Dimensional analysis is use to express the system with as few Independent variables and as many dimensionless parameters as possible. 3. The values of the dimensionless parameters are held to be the akin for both the scale model and application.This croupe be done because they are dimensionless and pass on ensure dynamic similitude between the model and the application. The resulting equations are used to realise scaling laws which dictate model testing conditions. However, it is often impossible to achieve unappeasable similitude during a model test. The great the departure from the applications operating conditions, the more touchy achieving similitude is. Similitude is a term used widely in breaking mechanics relating to the strain life approach.Under tending(p) loading onditions the bear damage in an unnotched specimen is comparable to that of a notched specimen. Similitude suggests that the component fatigue life of the two objects will withal be similar. One example that we ignore give here Is the. Pipe crash apparatus has been designed for students to measure metro friction losses for laminar and t roubled currents. For laminar scat study, an elevated vanguard tank Is used for water supply, whilst for steamed move the supply is from the Hydraulics bench using oses with rapid action hosiery coupling.Students may control the flow rate of water by adjusting the flow governor valve. The test section is connected to manometers via force per unit area tapplngs. The purpose (objectives) doing this experiment are standard of the pressure loss for laminar flow Measurement of the pressure loss for degenerate flow Determination of the critical Reynolds be Measurements using a vacuum tube manometer Measurements using a mercury U tube manometer Reynolds number in pipe frictionPressure drops seen for in full developed flow of fluids through pipes git be predicted 1 OF2 uslng tne saturnine Olagram wnlcn plots tne Darcy-welsoacn Trlctlon Tactor T against Reynolds number Re and relative indenture. The diagram clearly shows the laminar, transition, and turbulent flow regimes as R eynolds number increases. The nature of pipe flow is strongly dependent on whether the flow is laminar or turbulent. using the Moody diagram which plots the Darcy-Weisbach friction factor f against Reynolds number Re and relative roughness . The diagram clearly shows the laminar,