Varying Mach Number with Design Points

QuantumAJ · February 4, 2019, 15:05

Hi,

I have a aerofoil modeled and meshed and I would like to vary the Mach number from 0.6 to 1.2. I have set up the boundary condtions such that the inlet velocity is a parameter and the farfield mach number is also a parameter. I would like to compute this range in small 0.5 increments and using the desing points would make easy work of this. My question is, if i change the mach number from design point to design point, do I loose my Initialization compute from and referance value.
For example, In DP 1, I compute from inlet with mach=0.6, in DP 2, is the inlet Initialization still m=0.6 or is it m=0.65 as defined in the table?

Thanks
Al

LuckyTran · February 4, 2019, 17:12

If you use "compute from" then it will use whatever properties are assigned to the boundary. So it will update to use the M=0.65.

But if you're going to vary the solution in small increments, it might be a better idea to just change the BC and not re-initialize. Just use the solution at M=0.6, change the mach number, and then keep iterating. The converged solution at M=0.6 might be a better initial condition than a blind initialization.

QuantumAJ · February 5, 2019, 05:10

Thank you for the reply LuckyTran.

Im looking to plot the Cd and Cl vs Mach number on a graph, would this be the best method of obatinign the data? I like the design points as I can export it to .cvs file.

February 4, 2019, 15:05	Varying Mach Number with Design Points	#1
QuantumAJ New Member Alex Join Date: Feb 2019 Posts: 4 Rep Power: 7	Hi, I have a aerofoil modeled and meshed and I would like to vary the Mach number from 0.6 to 1.2. I have set up the boundary condtions such that the inlet velocity is a parameter and the farfield mach number is also a parameter. I would like to compute this range in small 0.5 increments and using the desing points would make easy work of this. My question is, if i change the mach number from design point to design point, do I loose my Initialization compute from and referance value. For example, In DP 1, I compute from inlet with mach=0.6, in DP 2, is the inlet Initialization still m=0.6 or is it m=0.65 as defined in the table? Thanks Al

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February 4, 2019, 17:12		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,764 Rep Power: 66	If you use "compute from" then it will use whatever properties are assigned to the boundary. So it will update to use the M=0.65. But if you're going to vary the solution in small increments, it might be a better idea to just change the BC and not re-initialize. Just use the solution at M=0.6, change the mach number, and then keep iterating. The converged solution at M=0.6 might be a better initial condition than a blind initialization.

February 5, 2019, 05:10		#3
QuantumAJ New Member Alex Join Date: Feb 2019 Posts: 4 Rep Power: 7	Thank you for the reply LuckyTran. Im looking to plot the Cd and Cl vs Mach number on a graph, would this be the best method of obatinign the data? I like the design points as I can export it to .cvs file.