You explained this incredibly well. Coming from an engineering student studying from home during the pandemic, your videos are a lifesavers. Thank you very much!
You are correct - if you look at the coordinate system that I draw at 1:42 you will see that the y-axis has a zero value at the center line of the channel.
Thank you. It's a really good explanation. But could I ask a question? what about the shear stress of the lower wall? if y= -0.25, then tau on fluid is positive,on the other hand, tau on wall is negative, so shear stress of the upper wall and lower wall are opposite directions. it's really confused.
Probably you have the answer to your question already but just want to mention that since it was found negative value on the upper plate that means shear is negative on upper plate. But area normal is negative on upper surface so by sign convention shear stress component on upper wall should act right direction. For lower plate same sign convention applies and you should have a positve stress.
My only question is that the "y" in your formula represented the distance between the plate and where Umax is located? Thank you for showing this example.
Also looking for a bit of clarification on this. I am assuming since we use Umax then we can also use y as the distance from the plate in the equation.
The coordinate system is defined at the centerline of the channel. The y in the last equation is the y-location of the upper wall - so half the channel width.
I think it came from interpolating the values from the table A.1 I interpolated and got 0.001155 so I guess it's about right with different tables and slightly different numbers
He explains in the video since the derivation for tau, mu times du/dy finds the shear on the fluid. We can then deduce that the shear on the plate is opposite in direction so flip the sign.
You explained this incredibly well. Coming from an engineering student studying from home during the pandemic, your videos are a lifesavers. Thank you very much!
th-cam.com/video/XPCgGT9BlrQ/w-d-xo.html 💐💐💐💐
Gracias, tus videos también ayudan a gente que habla otro idioma
Thank you! It's really helpful to watch someone go through the motions.
You are correct - if you look at the coordinate system that I draw at 1:42 you will see that the y-axis has a zero value at the center line of the channel.
I came looking for how I can understand the sign of the answer and I got it plus an explanation for why that is. Great content :)
th-cam.com/video/XPCgGT9BlrQ/w-d-xo.html 💐💐💐💐
Thank you, professor.
Thank you so much sir. Your concept is very clear. You are great.
Great video
This velocity profile doesn't make sense to me. The velocity is moving backwards at the wall (y= +/- h)?
Where the Y value is coming from?
Perfect language. Thank You Sir!
Thank you. It's a really good explanation.
But could I ask a question? what about the shear stress of the lower wall? if y= -0.25, then tau on fluid is positive,on the other hand, tau on wall is negative, so shear stress of the upper wall and lower wall are opposite directions. it's really confused.
Did you get an answer for this? I have the same problem in understanding. Cheers
I think a good way to understand this is since y is a “distance” we take the absolute value of it yielding the same sign for the shear
Probably you have the answer to your question already but just want to mention that since it was found negative value on the upper plate that means shear is negative on upper plate. But area normal is negative on upper surface so by sign convention shear stress component on upper wall should act right direction. For lower plate same sign convention applies and you should have a positve stress.
My only question is that the "y" in your formula represented the distance between the plate and where Umax is located? Thank you for showing this example.
Also looking for a bit of clarification on this. I am assuming since we use Umax then we can also use y as the distance from the plate in the equation.
Where did the value for y come from?
Half of the height, since Umax is halfway between the two plates.
Thank you for this sir. Very helpful!
How did u get value for y? Is it given in question?
Half the “height”, h, or the distance between the two plates
since we are looking at Umax which is located at the middle point between the two plates
Sir, when will fluid flow at any value of shear force or it should be greater than the viscosity of fluid?
can you please tell me where does 0.25 came from? ... I mean the y in last equation
The coordinate system is defined at the centerline of the channel. The y in the last equation is the y-location of the upper wall - so half the channel width.
@@ronhugo6225Thank you
won't Shear stress equal - of viscocity * velocity gradient
y = 0.25 ×10^-3 where did that came from sir?
it is the distance from the umax, (center) to the top
How value of mew is calculated?
I think it came from interpolating the values from the table A.1
I interpolated and got 0.001155 so I guess it's about right with different tables and slightly different numbers
th-cam.com/video/XPCgGT9BlrQ/w-d-xo.html 💐💐💐💐
how is 0.5mm equal 0.005 m, it would not be 0.0005?
h in the denominator is 0.5 X 10^-3 m which is 0.0005 m
why the result changed from -3.12 N/m² to +3.12 N/m², please explain 🙏
He explains in the video since the derivation for tau, mu times du/dy finds the shear on the fluid. We can then deduce that the shear on the plate is opposite in direction so flip the sign.
For y=h τ=μ*(du/dy)* (π/2) = 0.0013*(0.30/(0.00025) *(π/2)= 2.449
For y=-h τ=-2.449