 Satchin Deshmukh working as assistant professor in the department of civil engineering of vulture and stuff technology of Solapur. Today we are going to learn the impact of jet on stationary flat plate and as well as inclined plate. At the end of this topic you will be able to find the force exerted by a fluid jet on stationary flat plate and inclined plate. The application of this impact of jet is particularly in the pelton wheel we can see. But before that we will go through the introduction of this impact of jet, a jet of fluid emerging from a nozzle, nozzle when the diameter is reduced and a jet is coming out. The nozzle has some velocity and hence it possesses a certain amount of kinetic energy. If this jet strikes on the obstruction placed in its path, it will exert a force on the obstruction. This impressed force of that particular jet is known as impact of jet. In this session we are going to see two different cases of force exerted by free jet on flat plate normal to the jet and flat plate inclined at angle theta to the jet have been seen. Now just I told that one of the application of the jet impact is used to generate electricity. Impact of jet is used to rotate the turbine particularly the pelton wheel in the generator. The water jet is applying force tangential to the wheel, see here tangential to the wheel, the tangential forces of the water jet generate moment, generate moment it rotates generate moment or torque on the wheel to its maximum value and therefore increase the mechanical energy of the pelton wheel. The rotational energy when it is going to rotate the rotation energy of the wheel is then converted into electrical energy, this figure of the pelton turbine, this jet which is going to impact on these cups mounted on the wheel and it rotates. The main parts are given penstock, runner, then casing, bucket, nozzle, then the hand of the wheel, spear and water jet. Here also you can see this figure how the jet is applied clearly and it rotates. To predict the output of a pelton wheel and to determine its optimum rotational speed we need to understand how the deflection of jet generates a force on the buckets and how the force is related to the rate of momentum flow in the jet. So particularly when we are going to experimentize it, we measure the force generated by jet of water striking flat plate or inclined plate and compare the results with the computed momentum flow rate in the jet. First of all we will discuss about the flat plate normal to the jet. See here it is a pipe to the pipe, nozzle is fixed and from this nozzle the jet of water which is striking to this plate, this is the normal plate. Now we can see here after striking the water goes along this plate, normal to this plate is the v is velocity. Now we will find the expression for this, d is the jet diameter v is the velocity issued from that nozzle of the jet, a is area of cross section, w is specific weight of the fluid, m is mass it may express now it may express as wav upon g, mass is wav upon g and discharge is area that is pi d square by 4 into velocity. Then the force exerted by the jet on the plate in the direction normal to the plate is determined as minus f because the negative sign shows the force exerted by the plate on the jet on the opposite direction x direction. So minus f is equal to wav upon g, it is the initial and final velocity, final and initial you can see. So only v remains so wav square upon g minus get cancel f you will get wav square upon g when it is normal, when it is normal keep in mind f is equal to wav square upon g when the plate is normal. Second condition see here same the pipe, the nozzle then the jet but the plate is inclined but the plate is inclined. Now here the jet goes over here this line here we have to find out fx and fy two different see here fx and fy two different forces we are going to find out this is a v sin theta v sin theta this is the inclined plate. Here theta is the angle between jet and plate m is the mass of the fluid wav upon g where all the notations are same as defined in the previous one. The component of the velocity of the jet v sin theta this one v sin theta therefore by the applications of the impulse momentum equation the thrust exerted by the jet in the direction normal to the plate is expressed as now f is equal to as previous one as we have taken for the normal that is wav upon g here the velocity component v sin theta and the final is 0. So f is equal to wav into vv square sin theta upon g keep in mind f is equal to wav square sin theta upon g but we have to calculate the fx and fy as these are the two different components see here fx and fy these are two components that we have to find out. The dynamic thrust f is resolved in two components that is fx which is parallel to the direction of the jet and fy normal to the direction of jet when it is parallel it is sin theta induced f sin theta that is wav square sin theta upon g and when it is normal to the direction of jet it is f cos theta so wav square sin theta cos theta upon g we will see the one problem on this we will solve one problem that is a jet of water 75 millimeter diameter having the velocity of 20 meter per second strikes a normally flat smooth plate and find out the thrust on the plate at rest. The normal thrust on the stationary plate f is equal to wav square upon g so area of jet it is pi d square by 4 75 upon 1000 it is 75 millimeter that is why it is divided by 1000 converted into meter so area of jet is 0.00442 meter square velocity of jet it is given to us that is 20 meter per second put this value 9810 g 0.0042 into this v square upon g we get 1768 Newton that is 1768 Newton force or you can say thrust on the plate which is at rest. Similarly we can solve for when the plate is kept inclined angle is given to us we can put this values and we can find out fx and fy also. Now these are some objective type of questions for you take a pause and go through these questions very important questions these are the answers for these questions for this you can refer books which are related with fluid machinery where you can study pumps where you can study turbines so you can refer many books also you can refer the Modi set you can refer also you can refer Bansal you can refer Rajput also go through these books also thank you.