# Search results

1. ### Probability Density Functions in Fluid Mechanics

Think I'm a step closer - for the u=sin(wt) function, what Ive done is basically made a histogram by taking small increments of du, say 10, and finding the range of t values that will occupy that specific segment. After normalising the areas so summed they all equal 1, you plot it as a histogram...
2. ### Probability Density Functions in Fluid Mechanics

Apologies, I'll try to be more specific, see if that helps. Although the wording for the question applies also to random data, and the same question has been asked for random data, ie: "Sketch a random signal u(t) as a function of time t and use the Graphical Technique to find the PDF" Another...
3. ### Probability Density Functions in Fluid Mechanics

And unfortunately I was foolish enough to leave this to 24hrs before the exam, please guys anything you can offer would be great!
4. ### Probability Density Functions in Fluid Mechanics

Hi all, For an exam I'm required to be able to plot the PDF of a fluctuating velocity function, say u(t)=sint(wt), using what they call the "graphical technique", but handily I can't find it anywhere in the lecture notes, and I'm struggling to find anything with a standard Google search...
5. ### Friction Velocity from Law of the Wall

Hi all, Am currently studying a set of data from a Hot Wire Anemeotry lab that was done a few days ago. The experiment was investigating a turbulent flow of air in a wind tunnel near a flat wall. As part of the write up, we're ment to find the friction velocity from the laminar near wall...
6. ### Fluid Dynamics - Spanwise Vorticity of Turbulent Boundary Layer

Yup that does sound all very much out of my league at the moment. And agreed as well that I'm not sure I could see the aim of studying the effect of acoustic disturbance on a turbulent boundary layer - our tutor's been emphisizing how important it is to have a measurable property at the centre...
7. ### Fluid Dynamics - Spanwise Vorticity of Turbulent Boundary Layer

Yeah, my project tutor didn't sound too convinced when I pitched it to him. I'm genuinely struggling here, any suggestions for what might make a good project in this area?
8. ### Fluid Dynamics - Spanwise Vorticity of Turbulent Boundary Layer

Hi Vadar, any sources to help demistify the topic would be very much appreciated, as it also looks like I'm steering my final year project towards something in this subject area. I think one of the things that is drawing me towards this subject matter is the inherent difficulty with which one...
9. ### Fluid Dynamics - Spanwise Vorticity of Turbulent Boundary Layer

Sorry for the delay in reply all, and thank you for your reply's! What I believe I've read and understood is that these low speed streaks that occur due to span wise variations in velocity actually have a pattern to them. When readings are taken over a long enough time period, a pattern emerges...
10. ### Fluid Dynamics - Spanwise Vorticity of Turbulent Boundary Layer

Hi all, Am reading a few papers for a Uni case study about structures in Turbulent Boundary Layers over a Flat Plate (water), particularly low-speed streaks. I'm confused over what mechanism causes the span wise variations in velocity that seems to cause low speed streaks. Would...
11. ### Hi new to this fluid mechanics help needed

From q=Fx/uA: - Multiply both sides by u to get: qu=Fx/A - Then divide both sides by q to get: u=Fx/Aq Hope it helps. And it might be an idea to be polite mate, not every question can get answered with 30 mins!
12. ### First Order Control System

Have gotten something like: (R^2(K^2.Hi + K.Qd(s)) - R(K.Hi + Qd(s))) / (R^2(A.K.s + K^2) - R.A.s -1
13. ### First Order Control System

Yeah, I can't do it. Have been trying for a bit now, wasting far too much time on something this simple!
14. ### First Order Control System

Think that's it! Know its pretty stupid, but I can't get any sense out of the division. Not a good sign to get to 2nd year Uni without learning algebraic division :/ Thanks again!
15. ### First Order Control System

Yes mate, thats the one. I know that I'm being a bit of a moron with this one, but its just left me. Watching youtube vids as well to help bring it back, but I think just having one example from someone else with one of these that is related to this topic area as well would be a great help, even...
16. ### First Order Control System

Hi all, got a Control question here, and I'm struggling with what I assume is a simple algebraic step. Thanks in advance! 1. Homework Statement A closed loop control system governs the level of water in a tank (H(s)) to meet a target height (Hi(S)). The flow of water into the tank is...
17. ### Electromagnetic Induction in the Earths Field

Hi all, brand new to these forums but help you can give me some guidance with some summer exam revision! Heres a fairly simple one I can't see through for some reason, using EMF = B.u.l etc: 1. A copper disc, 250mm in diameter, is reotated at 300 rpm about a horizontal axis through its centre...