Total pressure - Revision history

en>Dolphin51: Reverted good-faith edit by Mermaldad (talk). Total and stagnation pressures are numerically equal, but they aren't synonymous.

2014-12-13T11:09:38Z

Reverted good-faith edit by Mermaldad (talk). Total and stagnation pressures are numerically equal, but they aren't synonymous.

← Older revision		Revision as of 13:09, 13 December 2014
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	~~'''Dunkerley's method'''~~ is ~~used in mechanical engineering to determine the critical speed of a shaft-rotor system~~. ~~Other methods include the [[Rayleigh–Ritz method]].~~		Nice to meet you, my name is Ling and I completely dig that title. Alabama is exactly where he and his wife reside and he has everything that he requirements there. What she enjoys doing is bottle tops collecting and she is trying to make it a occupation. Bookkeeping is what I do for a residing.<br><br>Also visit my website; [http://kjhkkb.net/xe/notice/409153 kjhkkb.net]

	~~==Whirling of a shaft==~~

	~~No shaft can ever be perfectly straight or perfectly balanced~~. ~~When an element of mass~~ is a distance ‘ ’ from the axis of rotation, centrifugal force, will tend to pull the mass outward. The elastic properties of the shaft will act to restore the “straightness”. If the frequency of rotation is ~~equal~~ to ~~one of the resonant frequencies of the shaft, whirling will occur. In order to save the machine from failure, operation at such whirling speeds must be avoided~~. ~~Whirling~~ is a ~~complex phenomenon that can include harmonics but we are only going to consider synchronous whirl, where the frequency of whirling is the same as the rotational speed.~~

	~~==Dunkerley’s formula (approximation)==~~

	~~The whirling frequency of a symmetric cross section of a given length between two points is given by:~~

	~~:<math> N = {94~~.~~251} \sqrt{E\ I \over m\ L^3} \! </math> RPM~~

	~~where~~
	~~E = young's modulus~~
	~~I = Second moment of area,~~
	~~m = mass of the shaft,~~
	~~L= length of the shaft between points~~

	~~A shaft with weights added will have an angular velocity of N (rpm) equivalent as follows:~~

	:<~~math~~>
	~~\frac{1}{N_N^2} = \frac{1}{N_A^2} + \frac{1}{N_B^2} + \cdots + \frac{1}{N_n^2}~~
	<~~/math~~>

	~~==Background information==~~

	*[[Vibration]]
	*[[Mechanical resonance]]

	[[~~Category~~:~~Mechanical engineering]~~]

en>Hhhippo: Categories, wikilinks, identation

2012-09-24T21:09:30Z

Categories, wikilinks, identation

← Older revision		Revision as of 23:09, 24 September 2012
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	~~Friends contact him Royal~~. The ~~favorite pastime for him and his children~~ is to ~~play badminton~~ but he is ~~having difficulties to find time for it~~. ~~Alabama has always been his house and his family members enjoys it~~. ~~Interviewing is how~~ I ~~make a residing and it~~'s ~~some thing~~ I ~~really appreciate.~~<br><br>~~Also visit my page; [http://www.holzkunst-Scholz.de/index.php?mod~~=~~users&action~~=~~view&id~~=~~7124 www.holzkunst-Scholz.de~~]		'''Dunkerley's method''' is used in mechanical engineering to determine the critical speed of a shaft-rotor system. Other methods include the [[Rayleigh–Ritz method]].

			==Whirling of a shaft==

			No shaft can ever be perfectly straight or perfectly balanced. When an element of mass is a distance ‘ ’ from the axis of rotation, centrifugal force, will tend to pull the mass outward. The elastic properties of the shaft will act to restore the “straightness”. If the frequency of rotation is equal to one of the resonant frequencies of the shaft, whirling will occur. In order to save the machine from failure, operation at such whirling speeds must be avoided. Whirling is a complex phenomenon that can include harmonics but we are only going to consider synchronous whirl, where the frequency of whirling is the same as the rotational speed.

			==Dunkerley’s formula (approximation)==

			The whirling frequency of a symmetric cross section of a given length between two points is given by:

			:<math> N = {94.251} \sqrt{E\ I \over m\ L^3} \! </math> RPM

			where
			E = young's modulus
			I = Second moment of area,
			m = mass of the shaft,
			L= length of the shaft between points

			A shaft with weights added will have an angular velocity of N (rpm) equivalent as follows:

			:<math>
			\frac{1}{N_N^2} = \frac{1}{N_A^2} + \frac{1}{N_B^2} + \cdots + \frac{1}{N_n^2}
			</math>

			==Background information==

			*[[Vibration]]
			*[[Mechanical resonance]]

			[[Category:Mechanical engineering]]

en>Dolphin51: Cancelled re-direct. Total pressure and stagnation pressure are numerically equal but they aren't the same. Like "F" and "ma" are numerically equal but not the same thing.

2011-12-15T21:47:30Z

Cancelled re-direct. Total pressure and stagnation pressure are numerically equal but they aren't the same. Like "F" and "ma" are numerically equal but not the same thing.

New page

Friends contact him Royal. The favorite pastime for him and his children is to play badminton but he is having difficulties to find time for it. Alabama has always been his house and his family members enjoys it. Interviewing is how I make a residing and it's some thing I really appreciate.<br><br>Also visit my page; [http://www.holzkunst-Scholz.de/index.php?mod=users&action=view&id=7124 www.holzkunst-Scholz.de]