Hello,
I think this is more a setup error than an issue with the solver itself. I am currently studying the PRANDTL-D flying wing (the one with 3.75 m span) and i cannot get the Nonlinear Lifting-Line solver to converge.
AeroBuildup, VLM and LL already ran with success (though with increased runtime), and I have followed the steps as provided in the NACA RM A50K27 example. The alpha sweep I have is a large, from -18 to 10 degrees, accounting for the 8 at the root, and I narrowed it for thie NLLL, while also decreasing the spanwise resolution to 3, which totals to about 120 panels.
Below is the snipped of the code I implemented:
`nlll_op_point = op_point.copy()
nlll_op_point.alpha=np.linspace(-14, 6, 10)
nlll_aeros=[
asb.NonlinearLiftingLine(
airplane=airplane,
op_point=op,
xyz_ref=xyz_ref,
spanwise_resolution=3,
spanwise_spacing_function=np.cosspace,
verbose=True,
).run()
for op in nlll_op_point
]
nlll_aero={}
for k in nlll_aeros[0].keys():
nlll_aero[k]=np.array([aero[k] for aero in nlll_aeros])
nlll_aero["alpha"]=nlll_op_point.alpha
nlll_aero`
Some operating points converged, as shown in the first image, but then the error on the second one appeared, so I do not know how to proceed.
I previously studied the PRANDTL-D with only the root and tip airfoils, and it converged, so maybe its spanwise washout nonlinearity made the solver struggle, though I am not entirely sure. I appreciate any help on this subject. Have a nice week :)
Hello,
I think this is more a setup error than an issue with the solver itself. I am currently studying the PRANDTL-D flying wing (the one with 3.75 m span) and i cannot get the Nonlinear Lifting-Line solver to converge.
AeroBuildup, VLM and LL already ran with success (though with increased runtime), and I have followed the steps as provided in the NACA RM A50K27 example. The alpha sweep I have is a large, from -18 to 10 degrees, accounting for the 8 at the root, and I narrowed it for thie NLLL, while also decreasing the spanwise resolution to 3, which totals to about 120 panels.
Below is the snipped of the code I implemented:
`nlll_op_point = op_point.copy()
nlll_op_point.alpha=np.linspace(-14, 6, 10)
nlll_aeros=[
asb.NonlinearLiftingLine(
airplane=airplane,
op_point=op,
xyz_ref=xyz_ref,
spanwise_resolution=3,
spanwise_spacing_function=np.cosspace,
verbose=True,
).run()
for op in nlll_op_point
]
nlll_aero={}
for k in nlll_aeros[0].keys():
nlll_aero[k]=np.array([aero[k] for aero in nlll_aeros])
nlll_aero["alpha"]=nlll_op_point.alpha
nlll_aero`
Some operating points converged, as shown in the first image, but then the error on the second one appeared, so I do not know how to proceed.
I previously studied the PRANDTL-D with only the root and tip airfoils, and it converged, so maybe its spanwise washout nonlinearity made the solver struggle, though I am not entirely sure. I appreciate any help on this subject. Have a nice week :)