Critical depth is not good for design because it represents an unstable energy state which makes it difficult to estimate the design depth (estimated flow depth + freeboard). There is already too much unquantified uncertainty in open channel computations. Designing a channel at critical depth introduces additional uncertainty which makes the potential design flow depth even less reliable. For the second part of your question, you ask, why is it changing the flow rate? I'm not sure what you might be referring to here. If you could clarify this question I'll be happy to answer.
The Critical Depth represents the point where the open channel flow changes between super and subcritical flow regimes. The water is still flowing, whether it be above or below the critical depth. It is a way of classifying the flow as being dominated by potential energy (i.e. sub-critical flow, or when the flow depth is greater than the critical depth) or dominated by kinetic energy (i.e. super-critical flow, or when the flow depth is less than the critical depth). I hope that helps.
Hi Sir. Thank you for replying. Just to clarify, what I meant was what will happen if the energy is lower than critical energy. Will the flow stop all together? Another question I'm wondering is how do you derive a specific energy curve for a constant q. It doesn't make sense to me as a layman trying to understand this topic, becos if there is a loss of energy when say the flow meets a hump and it results in loss of energy, why didn't the q reduce to a lower value . Will appreciate if you could answer! Thk you!!!
The total energy in an open channel will not go below the critical energy. Theoretically, the water depth can increase so much that the velocity is very small, but it will never reach '0'. As for your other question: this video shows how derive a specific energy curve in an open channel when Q is held constant (while we vary the flow depth). So I think you may not have understood that part. To address your final comment: For Q to change, you must be adding it, or taking it out. if no Q is being added or subtracted a bump in the channel will not change the Q because that would violate the law of conservation of mass.
This is Ayele from Ethiopia. the lecture is good and very interesting . i am forced to ask you some critical question. i am doing my research on predicting sediment response of the study area.So, having this, i should have true stream discharge but i can't because of the fact that the stream gauge taken from rectangular culvert.the culvert is not lied and flat or horizontal and the depth of the culvert increase from inlet to some distance of the culvert and decrease near to outlet of the culvert. due to this reason there is eddy in the culvert.i use floating material to have velocity and the culvert is graduated in the inlet but the depth i get is not true and velocity too.the data is already started to collect since 2014 and continue to 2018.so, how to correct the collected data? please help me! Thank you.
This is difficult because it seems to me, as best as I can understand, that the measuring gauge was installed in a location that should not have been used for measuring, and now you are interested in finding out if you can salvage the data that was collected? This is tricky and not a situation I have encountered. I wonder if anyone else has some insight into your problem.
Dear sir upload one another lecture about sections of open channel flow how to derive the derivations of open channel section rectangular , trapaezoidal , triangular and circular channel section
My highschool physics teaher want us to do this and nowhere on the book do they explain what the fuck this is. Also we have no calc yet :)) i want to die
Let me know if there is anything I can do to help you work through it. Perhaps I can create another video showing how to create this graph in Excel. Would that be helpful?
I paused 35 seconds. Maybe he explains it further in but an open channel? like a river channel? water? doesn't explain really explain to start what he is talking about.
That actually made.. . A TON OF SENSE.. Thanks
Thank you Kenneth Lamb.
Thank you very much for your videos
"If you enjoyed your first term of calculus" LOL
Your video explains very critical concept of water resources!
Thankyou so much
Very well explained. Easy to follow. Best lecture. Thank you.!!
Sir I have a doubt. Why the critical depth is not good for design. Why it is changing the flow rate
Critical depth is not good for design because it represents an unstable energy state which makes it difficult to estimate the design depth (estimated flow depth + freeboard). There is already too much unquantified uncertainty in open channel computations. Designing a channel at critical depth introduces additional uncertainty which makes the potential design flow depth even less reliable.
For the second part of your question, you ask, why is it changing the flow rate? I'm not sure what you might be referring to here. If you could clarify this question I'll be happy to answer.
Very well explained
Your video is very helpful for understanding specific energy also I huge like your lecture thank you
Good video.
Very good teory video
You are a beast 😂
6 min was better than 2 hour's
awesome
Can u please tell which software u have used??
Software used to create video: Doceri
Software used to analyze open channels: Excel & HEC-RAS
What happened after critical depth? Water stop flowing?
The Critical Depth represents the point where the open channel flow changes between super and subcritical flow regimes. The water is still flowing, whether it be above or below the critical depth. It is a way of classifying the flow as being dominated by potential energy (i.e. sub-critical flow, or when the flow depth is greater than the critical depth) or dominated by kinetic energy (i.e. super-critical flow, or when the flow depth is less than the critical depth).
I hope that helps.
Hi Sir. Thank you for replying. Just to clarify, what I meant was what will happen if the energy is lower than critical energy. Will the flow stop all together? Another question I'm wondering is how do you derive a specific energy curve for a constant q. It doesn't make sense to me as a layman trying to understand this topic, becos if there is a loss of energy when say the flow meets a hump and it results in loss of energy, why didn't the q reduce to a lower value . Will appreciate if you could answer! Thk you!!!
The total energy in an open channel will not go below the critical energy. Theoretically, the water depth can increase so much that the velocity is very small, but it will never reach '0'.
As for your other question: this video shows how derive a specific energy curve in an open channel when Q is held constant (while we vary the flow depth). So I think you may not have understood that part.
To address your final comment: For Q to change, you must be adding it, or taking it out. if no Q is being added or subtracted a bump in the channel will not change the Q because that would violate the law of conservation of mass.
I like your explanations master.
thank you in advance
This is Ayele from Ethiopia. the lecture is good and very interesting . i am forced to ask you some critical question. i am doing my research on predicting sediment response of the study area.So, having this, i should have true stream discharge but i can't because of the fact that the stream gauge taken from rectangular culvert.the culvert is not lied and flat or horizontal and the depth of the culvert increase from inlet to some distance of the culvert and decrease near to outlet of the culvert. due to this reason there is eddy in the culvert.i use floating material to have velocity and the culvert is graduated in the inlet but the depth i get is not true and velocity too.the data is already started to collect since 2014 and continue to 2018.so, how to correct the collected data? please help me!
Thank you.
This is difficult because it seems to me, as best as I can understand, that the measuring gauge was installed in a location that should not have been used for measuring, and now you are interested in finding out if you can salvage the data that was collected? This is tricky and not a situation I have encountered. I wonder if anyone else has some insight into your problem.
Dear sir upload one another lecture about sections of open channel flow how to derive the derivations of open channel section rectangular , trapaezoidal , triangular and circular channel section
Thank you Sir, Highly useful
EXCELLENT
Nice
dutty af
Is it ok if I assume this ia a positive comment?
My highschool physics teaher want us to do this and nowhere on the book do they explain what the fuck this is. Also we have no calc yet :)) i want to die
Let me know if there is anything I can do to help you work through it. Perhaps I can create another video showing how to create this graph in Excel. Would that be helpful?
I paused 35 seconds. Maybe he explains it further in but an open channel? like a river channel? water? doesn't explain really explain to start what he is talking about.
Yes, this video applies to open channel flow, like a river.