Dynamic stall NACA0012 Michael Alletto - Revision history

Michael Alletto at 20:51, 31 January 2024

2024-01-31T20:51:38Z

Michael Alletto: /* Lessons learned */

2022-01-09T13:16:31Z

Lessons learned

Michael Alletto: /* Periodically pitching case */

2022-01-09T12:02:36Z

Periodically pitching case

Michael Alletto: /* Periodically pitching case */

2022-01-09T11:58:10Z

Periodically pitching case

Michael Alletto: /* Periodically pitching case */

2022-01-09T11:57:32Z

Periodically pitching case

Michael Alletto: /* Periodically pitching case */

2022-01-09T11:54:19Z

Periodically pitching case

Michael Alletto: /* Static case for an angle of attach of α = 10◦ */

2022-01-08T14:07:17Z

Static case for an angle of attach of α = 10◦

Michael Alletto: /* Static case for an angle of attach of α = 10◦ */

2022-01-08T13:37:41Z

Static case for an angle of attach of α = 10◦

Michael Alletto: /* Static case for an angle of attach of α = 10◦ */

2022-01-08T13:24:17Z

Static case for an angle of attach of α = 10◦

Michael Alletto: /* Static case for an angle of attach of α = 10◦ */

2022-01-08T12:13:22Z

Static case for an angle of attach of α = 10◦

@@ Line 3: / Line 3: @@
 * '''affiliation''': WRD MS
 * '''contact''': <mail address='michael.alletto@gmx.de' description='author'>click here for email address</mail>
-* '''OpenFOAM versions''': v2112
+* '''OpenFOAM versions''': v2312
 * '''Published under''': CC BY-NC-ND license ([https://creativecommons.org/licenses creative commons licenses])

← Older revision		Revision as of 13:16, 9 January 2022
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	== Lessons learned ==		== Lessons learned ==
		+
		+	* snappyHexMesh was not able to generate the boundary layer cells up to the trailing edge. A strategy to achieve a boundary layer cells down to the trailing edge would be to blunt the trailing edge or introduce a very small radius of curvature at the trailing edge.
		+
		+	* the nose of the airfoil should be refined a bit more
		+
		+	* Maximum lift and drag coefficients of a periodically pitching airfoil can be fairly well captured with the current coarse mesh. Some care has to be taken however, since the data do not coincide well with the reference experiment of [2] for the static case.
		+
		+	* The results of the γ Reθ model (it can model the laminar-turbulent transition in the boundary layer) agree better with the reference experiment of [2] than the k-omega SST model which can only model a fully turbulent boundary layer

	==References==		==References==

@@ Line 245: / Line 245: @@
 attached to fully stalled. The region of low velocity above the airfoil in the
 stalled stages is very large.
 ==   Lessons learned ==

@@ Line 237: / Line 237: @@
 the pitching angle α. It is evident that the simulated moment coefficient is
 much more noisy as the same quantity reported by the experiment.
 The figure shown below, represents the evolution of the velocity mag-
 nitude over a pitching cycle. It can be seen that the flow changes from
 attached to fully stalled. The region of low velocity above the airfoil in the
 stalled stages is very large.
 ==   Lessons learned ==

← Older revision		Revision as of 11:57, 9 January 2022
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	[[File:cd_dynamicstall_naca0012_alletto.png\|750px\|center\|Cd]]		[[File:cd_dynamicstall_naca0012_alletto.png\|750px\|center\|Cd]]
		+
		+
		+	The next figure shows the development of the lift coefficient Cl over the
		+	pitching angle α. What it is evident is that the maximum Cl goes well
		+	beyond the static values. The experimental values are reasonably well cap-
		+	tured. Here it has to be said the care has to be taken since the static values
		+	are quite off (see former chapter) and the agreement with the dynamically
		+	pitching experiment can be only be chance. There are some differences
		+	between the k-Omega SST model and the γ Reθ for a κ = 0.1. For the
		+	k-Omega SST model we observe a constant increase of the list until right
		+	before the airfoil starts the pitch down again. For the γ Reθ the lift increase
		+	is more rapidly for higher angles of attach. The reason is not clear. Regard-
		+	ing the dependency with the reduced frequency κ we have a reduction of the
		+	lift with this quantity. For the smallest value considered κ = 0.025 in the
		+	experiment we observe a lift before the airfoil pitches down. The simulation
		+	report a lift increase until the maximum angle of attach α. The reason is
		+	not known.
		+
		+	[[File:cl_dynamicstall_naca0012_alletto.png\|750px\|center\|Cl]]
		+
		+	The next figure shows the development of the moment coefficient Cm over
		+	the pitching angle α. It is evident that the simulated moment coefficient is
		+	much more noisy as the same quantity reported by the experiment.
		+	The figure shown below, represents the evolution of the velocity mag-
		+	nitude over a pitching cycle. It can be seen that the flow changes from
		+	attached to fully stalled. The region of low velocity above the airfoil in the
		+	stalled stages is very large.
		+
		+	[[File:cm_dynamicstall_naca0012_alletto.png\|750px\|center\|Cm]]
		+
		+	== Lessons learned ==

	==References==		==References==

@@ Line 212: / Line 212: @@
 the airfoil pitches down. The simulation report a drag increase until the
 maximum angle of attach α.
 ==References==

← Older revision		Revision as of 14:07, 8 January 2022
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	[[File:Results_contoursUmag_alletto_dynamicStall_naca0012_10degreesStatic.png\|600px\|center\|]]		[[File:Results_contoursUmag_alletto_dynamicStall_naca0012_10degreesStatic.png\|600px\|center\|]]
		+
		+	=== Periodically pitching case ===
		+
		+	The next figure shows the development of the drag coefficient Cd over the
		+	pitching angle α. What it is evident is that the maximum Cd goes well
		+	beyond the static values. The experimental values are reasonably well cap-
		+	tured. Here it has to be said the care has to be taken since the static values
		+	are quite off (see former chapter) and the agreement with the dynamically
		+	pitching experiment can be only be chance. There are some differences be-
		+	tween the k-Omega SST model and the γ Reθ for a κ = 0.1. For the k-Omega
		+	SST model we observe a sharp drag increase right before the airfoil starts
		+	the pitch down again. For the γ Reθ the drag increase is more gentle. The
		+	reason is not clear. Regarding the dependency with the reduced frequency
		+	κ we have a reduction of the drag with this quantity. For the smallest value
		+	considered κ = 0.025 in the experiment we observe a drag reduction before
		+	the airfoil pitches down. The simulation report a drag increase until the
		+	maximum angle of attach α.

	==References==		==References==

← Older revision		Revision as of 13:37, 8 January 2022
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	[[File:Table_results_alletto_dynamicStall_naca0012_10degreesStatic.png\|300px\|center\|]]		[[File:Table_results_alletto_dynamicStall_naca0012_10degreesStatic.png\|300px\|center\|]]
		+
		+
		+	The next figure shows the contour plot of the velocity magnitude for the
		+	k-Omega SST model (left) and the γ Reθ model (right). It is evident that
		+	for an angle of attache of α = 10◦ the k-Omega SST model predicts already
		+	a fully stalled flow regime. The γ Reθ model predicts a state where the
		+	trailing edge separation is moving upstream. This is the stage right before
		+	the fully stalled regime.
		+
		+	[[File:Results_contoursUmag_alletto_dynamicStall_naca0012_10degreesStatic.png\|600px\|center\|]]

	==References==		==References==

← Older revision		Revision as of 13:24, 8 January 2022
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−	[[File:Table_results_alletto_dynamicStall_naca0012_10degreesStatic.png\|~~200px~~\|center\|]]	+	[[File:Table_results_alletto_dynamicStall_naca0012_10degreesStatic.png\|300px\|center\|]]

	==References==		==References==

← Older revision		Revision as of 12:13, 8 January 2022
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−	[[File:Table_results_alletto_dynamicStall_naca0012_10degreesStatic.png\|~~500px~~\|center\|]]	+	[[File:Table_results_alletto_dynamicStall_naca0012_10degreesStatic.png\|200px\|center\|]]

	==References==		==References==