TECHNIQUE OF HYDRAULIC MODELS

Abstract

1.1. O,~...NW I have met Frith tower difficulties in oboorvationo ralatin trk the movemente f h+ venl, bcdioe, nct thotanding their stupendcuo dist ctceo away, then in invest igatin, the mveaerit of flo7ing grater which takes place bef ro our very oyc&' is reported tc hove been said by Galileo o+c ►e 400 years ego, which is entirely true even t r:- day. Poiloiing vorde of Iabtti±b are also equally true. i'Ve Mow that upto the prep 1nt time our kn fledge of hydraulics is extremely halted pa i.... oul rly the River Uydrauhtcs, for although soon of great €eniuo have applied tbe.moclvca to the otudy of hydraulics at various times, co are as yet after many centuries in almost complete ignorance of the true la to which the flow of eater is e:ub, eet; it is scarcely a century and half since by Ceene of oxport-montotion the duratic:n , vohumo and velocity of die-charge of water through any kind of orifice ma d.iocovored". ' ho lama govornin arm4y of the problems of flotiing wator are yet to be perfectly understood and all tho factors offoctin ouch Flow cannot be rationally analysed. Cater is not a perfect fluid and many chap. I IUTRO :.UCTI017 2 problcuo of orator fl.on tith +nhich the engineer 10 confront ad are not capable of rigrou mathooatical -ooi.ution and hence ariooa the nocoaoity of oxpor1ento in laboratory on ma dole and oboorvaticno on actual of oturou i Those results of onporizonte along with the fundamcntol lave offlowing + iat or load to the ovolut icn of solution of different practical problorao facing the engineers. I2urthoz*oro it in v orthwhil o to o Ludy the portornonoo on a model of a ayetcm before uodorteh-ing any big project as it io comparatively in«-oxpon-dye to modify 'the cons truc t icon of a modal an. thus covoral altornativo dceiana my be traod before adopting final one. Thin 4ll avoid 000tly mistakes to occur' . A modal in a dovioo chub to co related to a physical system that oboorvati~na on it may be iced to predict the performance of the physical system in the døoirod rcapoot. The physical oyctem for tizhioh the prodictiono are to be made is called tho , tom. In gonoral more than one typo of model may be uooful In prodiotin the behaviour of a given prototype. One typo way bo similar in appearance to the prototype whorow cnothor may bear no rcocmblanco to it.