This man is incredible. He helped me ace fluids and now I find he does heat transfer. Rarely do I find myself EXCITED to watch lectures, but when I am, it's when I watch Professor Biddle
Your focus on clearly defining q, q', q", and q dot is so helpful. I had so much confusion from my book calling your q Q, both your q' AND your q dot just "Qdot", and finally your q" qdot. It felt conpletely unintuitive, and made their equations confusing without units. Seeing your scripts and explanation of q" cleared so much up for me conceptually.
Dear prof. John, thanks for your fabulous videos which are of great help. Why time t is not a variable in the temperature function T = T(x, y, z)? If not, the general heat diffusion equation (2.19) would be problematic since the right term, the partial derivative of T with respect to t, must ALWAYS be 0. I think it should be T = T(x, y, z, t). However, you DID put time into consideration in the 2D case as is T = T(x, y, t). I googled only to find out that there's no detailed and convincing answer to this question.
for question 2.1 if dt/dx become smaller means that it hasa derivative if it has a derivative conduction should not be steady state according to heat conduction theory d^2T/dx^2=dT/dt can you explain
Well, steady state and 1-D heat transfer are actually not good assumptions for that case. For these assumptions d^2T/dx^2=dT/dt does not apply because your infinitesimal element should be taken as a slender element with the whole crossectional area.
It is a Taylor series approximation and since we are looking at an infitesimally small element, the higher order terms from the Taylor series can be neglected.
i think something is strange with the solution of the 2.1 problem, specifically the part where you find the T(x) profile. A(x) * dT/dx is a NEGATIVE constant, so dT/dx decreases in absolute value, but actually INCREASES with x, rather than decreases. therefore its derivative d²T/dx² is positive, therefore T(x) is concave UP. when the professor shows the slope of the profile "decreasing", it is actually decreasing in absolute value but actually moving from a large negative value to a small negative value, i.e. INCREASING.
It can be internally generated in the fluid element (maybe chemistry is occurring) or maybe heat entering from multiple directions (say, the left and bottom) flows out through another direction (say, the right).
JEISSON RODRIGUEZ actually it is a 2D problem that's why where ever u take Z it will get canceled in everywhere that's why its taken as 1 ...cos 2D problem only ..XAnd Y are considerable
Whch book is he referring to
TEXT: Introduction to Heat Transfer, By Bergman and Lavine, 6th Edition
Do you have link to download this ebook?
@@jackytan819 libgen
@@bhradramazani not available over there
This man is incredible. He helped me ace fluids and now I find he does heat transfer. Rarely do I find myself EXCITED to watch lectures, but when I am, it's when I watch Professor Biddle
So happy I found this series! I'm in heat transfer right now and my professor is the nicest guy ever but not the best educator.
Your focus on clearly defining q, q', q", and q dot is so helpful. I had so much confusion from my book calling your q Q, both your q' AND your q dot just "Qdot", and finally your q" qdot. It felt conpletely unintuitive, and made their equations confusing without units. Seeing your scripts and explanation of q" cleared so much up for me conceptually.
I love your handwriting!
Years of practice.
Love the lectures! camera operator is asleep most of the time though
lol, aliens try to contact at 4:21 (have sound on)
About time!
Dear prof. John, thanks for your fabulous videos which are of great help. Why time t is not a variable in the temperature function T = T(x, y, z)? If not, the general heat diffusion equation (2.19) would be problematic since the right term, the partial derivative of T with respect to t, must ALWAYS be 0. I think it should be T = T(x, y, z, t). However, you DID put time into consideration in the 2D case as is T = T(x, y, t). I googled only to find out that there's no detailed and convincing answer to this question.
Yes, if the system is not steady state then T is a function of t, too.
Wonderful Heat Transfer lectures ! ! !
for question 2.1 if dt/dx become smaller means that it hasa derivative if it has a derivative conduction should not be steady state according to heat conduction theory d^2T/dx^2=dT/dt can you explain
Well, steady state and 1-D heat transfer are actually not good assumptions for that case. For these assumptions d^2T/dx^2=dT/dt does not apply because your infinitesimal element should be taken as a slender element with the whole crossectional area.
Somebody plz help! I dont understand 2:41
Do u know why q(x+dx) = q(x)+d[q(x)dx]/dx?
It is a Taylor series approximation and since we are looking at an infitesimally small element, the higher order terms from the Taylor series can be neglected.
i think something is strange with the solution of the 2.1 problem, specifically the part where you find the T(x) profile. A(x) * dT/dx is a NEGATIVE constant, so dT/dx decreases in absolute value, but actually INCREASES with x, rather than decreases. therefore its derivative d²T/dx² is positive, therefore T(x) is concave UP.
when the professor shows the slope of the profile "decreasing", it is actually decreasing in absolute value but actually moving from a large negative value to a small negative value, i.e. INCREASING.
there is a minus sign in that equation
Thank you Sir!
It's a huge help
No problem.
How I wish I am in Dr. Biddle's heat transfer class...
Why is the q coming out of the differential element greater than the q that enters it? Where is that additional heat coming from?
It can be internally generated in the fluid element (maybe chemistry is occurring) or maybe heat entering from multiple directions (say, the left and bottom) flows out through another direction (say, the right).
@@CPPMechEngTutorials Thank you for your response :)
Why isn't the E(dot)'' gen included at 52:56 ?
he just didnt write it down because its 0
47:38 , I checked with the book. It does not match with the 2.31 !
me too
@@kc137 Mine doesn't match too. Ours are probably different editions.
Holy shit, I didn't know dr. Biddle had HMT courses. Yiss.
Why is one dz in the area?
JEISSON RODRIGUEZ actually it is a 2D problem that's why where ever u take Z it will get canceled in everywhere that's why its taken as 1 ...cos 2D problem only ..XAnd Y are considerable
supposed 1
I am still confused by the answers if we are in 2D then why we are considering the dz to be 1,we are in the xy plane only
Book: drive.google.com/file/d/1m77fN_lsk9tvJmVr1RcloH7-thuaTzlj/view?usp=sharing
anyone has the answer for 2.31 part b to find h?
There a copy of solution manual for book he used in internet just search about it
thank you so much you really help a lot
man I wish I got to study in this unversity
love from Pakistan , Sir
pkmkb
can you plz give the homework questions
محدش هنا بيتكلم عربي يقولي هي ماده ايه ولسنه كام
ديه heat transfer سنه تالته او رابعه هندسه ميكانيكا
What kind of a cameramen are you bro. Follow the proffesör dont sleep in the class
I actually like that he doesn’t follow his every movement since it allows me time to take a screenshot.
ptm lo ocupaba en español
oh these are waste