I'm looking at the dynamic state of heat transfer through a concrete slab. Suppose heat is turned on at t=0 and the coils/tubing are 6 inches below the surface. Is there a formula or way of calculating the temperature at the surface at time = t?
I found a formula for thermal lag on wikipedia...
Two questions. I have read that wind chill is a measurement (or calculation, more accurately) that describes how cold the wind feels, even though the wind isn't actually colder than still air. What I am wondering is why isn't the wind actually colder? If it is moving faster it is lower pressure...
Well, that is a bit off-topic :) But both the company of my current job and my prospective job do the manufacturing. I am not too worried, as there are some things that just can't be outsourced effectively. Manufacturing is where the real value is -- not just holding a place in the line of...
I am early in my career working for a small niche company right now, doing a lot of mechanical design. It seems like great experience to me; I am learning a lot about machine parts, manufacturing processes, and drawings. However, I might have an opportunity to move into a large, well-connected...
Thanks for that thorough explanation. Essentially, what is throwing me off was whether the pressure was really zero at the duct outlet. It is going to have a significant velocity for some distance after exiting, so I was thinking it must have a different pressure than the stagnant air. Because...
I only know the pressure at one location: immediately after the fan. I just know that at some point further down the duct, it will be at some lower pressure. I don't know the exact location where it will reach 10 psi. I just know that it is pulled from a room where it is roughly stagnant and...
Yeah, if I knew flow rate velocity would be simple. I don't know it. All I will know is:
- friction factor (using an estimated velocity)
- initial pressure
- duct length
- duct diameter
And it is assumed the air is room temperature. This is a determinate system. If you set up a pressure...
I don't remember why I said frictionless. I do want to account for friction, but I just don't care about a specific value right now. I will have one eventually, but right now I am just trying to get the concept straight.
I was reviewing the Darcy-Weisbach, and I can enter everything into it...
Suppose I have a straight, frictionless duct, with consistent cross-sectional area, and air is flowing straight through and exiting into a free stream. A fan at the beginning of the duct draws stagnant air at atmospheric pressure, and then the air exits the end of the duct into another room also...
I have read that many tea masters insist that when infusing a tea that requires less-than-boiling water, you should first let the water reach a full 100 degrees C and let it cool back down to the target temperature, rather than take it off the burner as it is approaching boiling. I think it was...
Oh wow, I thought I was getting the same thing. I don't know how I overlooked the (1/2), sorry.
Well, the point was that I formed a ring by subdividing the point mass, but that doesn't matter anymore.
I know. This is the formula I derived for a ring, not a disc. My question is why I ended up with the same formula as that of a disc. The derivation seems sound to me.