Wind turbine velocity triangle explained with ASHES - the wind turbine simulation software

[Music] hey guys are doing so in today's video we're going to have a look at the velocity triangle and faretta have a simple mode here the velocity triangle is something that's one of the fundaments of blade aerodynamics it's a little bit complicated but if you bear with me we should get around this I can close this to make it a little bit bigger and so yes this is our turbine and then I start have wind coming here which is this white arrow here and of course the wind makes the the turbine rotate and if I stop the simulation what we're going to be looking at is these things here these little arrows on the blades so I can right click and open the velocity triangle and this is what we're looking at so this looks a little bit complicated now there's a there are lots of things but we're not going to look at everything we're not going to look at these two here and I'm going to remove all the vectors right no one will go through them one by one during the video so what is important to understand here is that this this drawing that we have here represents these arrows so as the blades are rotating this little arrow is also rotating with it and that's what we are seeing so anything that happens here on the on the turbine we're gonna see here okay so the first thing that we can have look at is the wind velocity so if I click here we see that the wind velocity is this arrow here and that's what we have here if I decrease the wind velocity which I can do here I see how these decreases also and if I increase its this increases again okay the second velocity that we're gonna have look at is the rotational velocity which is this red vector here so the rotational velocity is due to the fact that the blades are rotating and because the blades are rotating this little element is exposed to a wind that comes towards it because this is moving into the wind so as you can guess if I open a velocity triangle at closer to the roots this rotational velocity is a little bit shorter if I go back to this one you can see that it's sorry we can say that it's a little bit longer okay so I will come back to the previous one so that's what we're looking at now there is a third velocity which is called the induced velocity and that's this one here I'm not gonna going to details into what the induced velocity is today but basically what it means is that there is a difference in the air velocity that is coming towards the air fault here at the leading edge and that's leaving after the Air Force after the trailing edge and this difference we represent with the induced velocity there's no air particle traveling at this velocity but it's just a tool that we use to to explain this difference in in velocities okay and if I sum up all these three velocities what I get is the relative velocity which is this green vector okay I can just remove these components and just keep in the relative velocity so what we're interested in now is when we have this relative velocity coming here what type of loads are applied to our wind turbine the first law that we have is called the lift force and it's this one here so it's this green vector the lift force is perpendicular to the to the relative velocity and it's called lift because on an airplane that would be the force that lifts the plane upwards and the other force that we have is the drag force which is this one here it's very very little is very small compared to the lift it's about 100 to 200 times smaller if the wind turbine is well designed and this one is in the same direction as the relative velocity so I can show you these two forces on the blade as well so I can click here and select lift and drag components and what you see now here on the turbine are the same the same vectors as you're seeing here so the green one here there is the lift force and the drag force well it's actually so small that we don't really see it I can go into wireframe mode and zoom in a little bit and here we can see there's some tiny little arrows which are the drag force which again is much smaller than the lift force okay I can get back to this mod and now if I sum up the lift and the drag force what I get is the total force which is of course almost the same as the leaf for since the drag force is so small I can remove the lift and the drag now and the next thing that we want to know is out of this total force what contributes to make the turbine rotates and that's what we call the torque force and the torque force is the projection of the total force in this plane in the rotor plane and that is the first that's gonna make our turbine rotates the other component would be like around here that's what we call the thrust force and that's the force that pushes the turbine backwards and again I can show you here if I remove the lift and the drag and I turn on the thrust and the torque we can see here the orange vectors which are which are the torque force and the blue vectors which are the thrust force and as you see the throat the torque force is the one that makes the term on rotate while the thruster is pushing my Tora my turbine backwards so it's interesting to see that even though we have such a high lift force and such a low drag force we still have much more of the much more first force this blue vector than torque force which is this this orange vector and of course we would like to have more torque because that's what makes our turbine rotate but the way turbines are designed today we always get much more thrust than torque okay so I can sum this up quickly the first thing that we have the first night we have is the wind velocity here and the rotational velocity due to the blades rotating we also have an induced velocity which is the difference between the incoming win here and the one that's living here so if I sum these three forces against the relative velocity and this relative velocity is going to give two loads on the air fall one is the lift force which is perpendicular to the relative velocity and one is the drag force which is parallel to the relative velocity the sum of these two forces gives us the total loads which is is black vector here and the total force we can divide into a thrust component which is this one here another component which is the one that makes the turbine read it okay and well that's all for today so this is not easy stuff if you have any doubts or suggestions just leave us a comment and we'll reply as soon as possible and in future videos we'll go more in details into some of the things that we've seen today so great thanks for watching and see you around [Music]

Channel: Ashes - Wind turbine simulation

Views: 49,193

Keywords: wind turbine, Aerodynamics, blade aerodynamics, wind turbine technology, lecture, course

Id: OOP6Mbn0Gbw

Length: 7min 26sec (446 seconds)

Published: Mon Mar 19 2018