Probably the 20th clip I've watched on B-pi Theorem and the only one that has made sense to me
@nashbatten8097 Жыл бұрын
I've been in college for over 3 years and this is the best professor i've ever had. Thank you for the past 8 minutes of my life.
@nezha31686 жыл бұрын
I just want to thank you from the bottom of my heart for this clear explanation!Thank you.
@lisandroluzzi84998 жыл бұрын
thank you so much for this video. literally searched everywhere for an explanation for this theorem and this is the only video that has helped me
@anthonynunez99483 жыл бұрын
qpaqw
@CristianLopez-gw9rx4 жыл бұрын
Your video is really clear. I have seen lot of videos about this topic, but most of them are confusing. Congrats for your method.
@JoniniTheChickenNugget27 күн бұрын
Really helped with my first biotransport exam!!!
@LearnChemE11 жыл бұрын
You are correct that we are plotting Re on the x-axis and we defined this earlier as Pi1'.
@LearnChemE11 жыл бұрын
You choose the same number as reference dimensions (i.e. length, time, mass).
@lockercoin36936 жыл бұрын
mechanical engineering student here it was brilliant!
@Jan_Heckmann4 жыл бұрын
Extremly interesting and good explained! Even as a somebody who doesnt speak English as native Language I got it all!
@syafiqshaikh69304 жыл бұрын
really helping for my final exam fluid you are the bestt brooooo -utm-
@franciscomendez93278 жыл бұрын
Hi there! How does one choose the repeating variables? What defines a repeating variable? I seem to follow the rest of the operation well but I've looked in many places and have not been able to understand how the repeating variables are identified and chosen. Thank you!
@LearnChemE7 жыл бұрын
You have to be able to cover the all the dimensions found in the dimensionless number. Also, since we can alter these in experiments, it helps to use ones we can typically control. There is another video on this topic, with additional helpful comments: kzbin.info/www/bejne/l3-co3Zsasesec0
@franciscomendez93277 жыл бұрын
Ok, thank you very much!
@gabrielmtoloko5 жыл бұрын
It's good to use geometric, kinematic, and dynamic variables as repeating variables
@jenniferbetley49557 жыл бұрын
Best tutorial for dimensional analysis out there! Thanks!
@abernish7039 жыл бұрын
This helped refresh me on the material for an exam. Thank you!
@tinyeung34682 жыл бұрын
Why isnt pi 2 prime the inverse of pi 2, like pi 1 prime?
@saadmasood87984 жыл бұрын
An extremely well rounded explanation
@naumanriyazmaldar4571 Жыл бұрын
Why didn't you choose dynamic viscosity as a repeating variable? and why did you choose the other three?
@lethukuthulavilakazi36462 жыл бұрын
That makes sense, but I get stuck as to how do I now use these Pi terms to my benefit? How do I end up plotting? Which values were used in the plot as these Pi terms still include a number of variables.
@yurigouveawagner94323 жыл бұрын
why not choose viscosity? you said we had to choose a number equal to the number of dimension types, but you also defined the number of dimension types using the chosen dimensions, right?
@scooner6717 жыл бұрын
pi 1 is the reciprocal of the Reynolds number, right? feel like that should be pi 1 prime at the end, but i may be wrong
@barquetique4 жыл бұрын
I'm not even english but this is saving my chem semester
@chemhub31593 жыл бұрын
What does "repeating" mean?
@camilanneo10 жыл бұрын
Very good explanation thank you!
@Peter_19869 жыл бұрын
He's using The Force, especially on 6:16.
@vamsikrishna37308 жыл бұрын
how do we choose the repeating variables???
@jacksonburek95087 жыл бұрын
You have to use your intuition
@collegecheme30778 жыл бұрын
As stated, step 1 is rather confusing. Were the variables chosen arbitrarily? Why were those variables chosen? Why not take others into consideration for instance the pressure or acceleration of the sphere? Wouldn't those affect the drag coefficient?
@jacksonburek95087 жыл бұрын
The variables weren't chosen arbitrarily, you need to use your intuition. The reason we could rule-out pressure is because we already included density, which is proportional to pressure in a compressible fluid. Therefore, the density term will account for a lot of the effects pressure has. I think we can rule out acceleration because we have included velocity, which is the integral of acceleration. The current velocity of the sphere is related to the past acceleration of the sphere, so velocity somewhat accounts for this. You should know that this is a low-order analysis, so it won't give an exact answer, but will get close. In reality, it might turn out that pressure and acceleration affect the drag force independently from the density & velocity. However, the low-order formula is simple to derive and probably does a good-enough job. I think the process of refining a model by adding higher-order corrections is the basis for perturbation theory, which is very applicable in fluid dynamics.
@arnar94782 жыл бұрын
I don't think you explained step 2 well enough? just choose any random variables doesnt matter what? I can just choose the diamater and be good?
@tymofei85864 жыл бұрын
Can someone explain whats significance of pi theorem? its just doesnt makes sense to me at all.We forcing terms to cancel each other and become dimensionless thats it.What does it give us mathematically what type of data and importance it have ? Why we able to multiply or divide extract.. PI terms without changing them or their significance ? Im looking for more intuitive explanation cause it looks nonsense to me...
@Ajiro0815 күн бұрын
How is force the dependent variable
@lasidiomas11 жыл бұрын
How did you chose to take exactly three repeating variables?
@mbordiermontes6 жыл бұрын
Thanks Knutsen :D
@knutejay5 жыл бұрын
:)
@elidavis54584 жыл бұрын
So much better than my teacher
@urbananime54849 жыл бұрын
where did A=(pi/4)d^2 come from?
@LearnChemE9 жыл бұрын
That is just the equation for area. Area = pi*r^2. r = D/2, so A = (pi/4)D^2.
@behappy52296 жыл бұрын
plz tell me how to select vescocity & density while both r fluid property
@閔鴻4 жыл бұрын
How to choose core variables? Thanks
@NEpatsfan939 жыл бұрын
are you always supposed to just choose 3 repeating variables?
@LearnChemE9 жыл бұрын
NEpatsfan93 You choose the same number as reference dimensions (i.e. length, time, mass).
@wanted_u Жыл бұрын
So helpful ❤
@MothyEmms7 ай бұрын
is this the only american youtuber who works in si units?
@Madvilllain11 жыл бұрын
For the last graph, I thought you had defined the Reynolds number to be Pi1' not Pi1. Could you explain this?
@connorskudlarek85985 жыл бұрын
Everything seemed good, until there was no explanation for the primes. Why is one inverted, but the other is some projected area? Why bother changing it? Why not leave it where it is?
@MoAtreides5 жыл бұрын
You have to manipulate them to get a term that exists, in this case it must be equal to the Reynolds number and coefficient drag. This is done so you can compare real terms.
@ibrahimkuru39104 жыл бұрын
mindblowing
@jasonbishop641611 күн бұрын
thank you you legend
@ThaoNguyen-dd5ef9 жыл бұрын
How did u calculate pi prime?
@LearnChemE9 жыл бұрын
Once you have the dimensionless number of pi, you can manipulate it to become a term of greater interest. In the first case, the reciprocal of the initial pi is the Reynold's number. In the second case, we merely replaced the diameter squared with area. Since we are only interested in the units and not the actual number, we are able to substitute a 1/2 for the 4/3.14, thus giving us the coefficient of drag.
@sultanloobari40378 жыл бұрын
very useful video
@CarinaArmoogam-f5x6 ай бұрын
THANK U
@cammys955210 жыл бұрын
Thank you :)
@imdssk8 жыл бұрын
Useful.....
@MisterFramboise26 күн бұрын
hey dady
@DrDerivative Жыл бұрын
Noice!
@TrinaTat4 жыл бұрын
how do I choose which variables are for repeating variables?