y+ is zero!!

AMAL13113 · May 16, 2024, 04:39

hello
I am simulating laminar flow on a flat plate using SU2 software, and the results show that y+ is always zero!!
I have also tried to run the laminar flat plate example that comes in the tutorial without changing anything, and it also gave this result

poly_tec · May 16, 2024, 07:39

thanks for sharing! /s

naffrancois · May 17, 2024, 03:37

y+ is needed if you use a turbulence model. A turbulent boundary layer is decomposed in various regions: a laminar sub-layer, a transition layer, a log layer.

For a flat plate the transition is located at y+ ~ 11. When y+ < 11 in the cells adjacent to the wall, then you have cells inside the laminar sub-layer and you do not need a wall function, you are actually solving the sub-layer.

When the flow is fully laminar, you do not use a turbulence model and your solver does not need y+ value.

May 16, 2024, 04:39	y+ is zero!!	#1
AMAL13113 New Member AMAL Join Date: May 2024 Posts: 1 Rep Power: 0	hello I am simulating laminar flow on a flat plate using SU2 software, and the results show that y+ is always zero!! I have also tried to run the laminar flat plate example that comes in the tutorial without changing anything, and it also gave this result

May 16, 2024, 07:39	y+ is zero!!	#2
poly_tec New Member Poly T Join Date: May 2022 Posts: 24 Rep Power: 3	thanks for sharing! /s

May 17, 2024, 03:37		#3
naffrancois Senior Member Join Date: Oct 2011 Posts: 242 Rep Power: 16	y+ is needed if you use a turbulence model. A turbulent boundary layer is decomposed in various regions: a laminar sub-layer, a transition layer, a log layer. For a flat plate the transition is located at y+ ~ 11. When y+ < 11 in the cells adjacent to the wall, then you have cells inside the laminar sub-layer and you do not need a wall function, you are actually solving the sub-layer. When the flow is fully laminar, you do not use a turbulence model and your solver does not need y+ value.