CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > SU2 > SU2 Shape Design

Total force optimization or pressure force optimization?

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By economon

LinkBack Thread Tools Search this Thread Display Modes
Old   July 3, 2013, 07:41
Default Total force optimization or pressure force optimization?
Roberto Pieri
Join Date: Feb 2012
Location: Milan
Posts: 57
Rep Power: 13
robyTKD is on a distinguished road
As written in the title, I would like to know if SU2 force optimization is based on this objective function:

J(S) = \int_S j (\mathbf{f}) \, ds = \int_S \mathbf{f} \cdot \mathbf{d} \, ds,


& \mathbf{f} = p \mathbf{n} - \underline{\underline{\bar{\sigma}}} \cdot \mathbf{n} \\
& p \mbox{ pressure} \\
& \underline{\underline{\bar{\sigma}}} \mbox{ tensor of viscous stresses} \\
& \mathbf{d} \mbox{ constant direction}

I found that only the pressure component of drag is reduced in the optimization framework, while friction component doesn't change.
Is this related to the absence of the tensor of viscous stresses in the equation of the shape sensitivity (eq. (35) of "Continuous Adjoint Approach for the Spalart-Allmaras Model in Aerodynamic Optimization"; Bueno-Orovio, Castro, Palacios, Zuazua) or to the definition of the objective function implemented in the code?
Another question: where can I found lines of the code where shape sensitivity is computed?
robyTKD is offline   Reply With Quote

Old   August 19, 2013, 16:54
Super Moderator
Thomas D. Economon
Join Date: Jan 2013
Location: Stanford, CA
Posts: 271
Rep Power: 13
economon is on a distinguished road
Hi Roberto,

Indeed, the force-based optimization in SU2 is based on the form of the objective function in your post. It turns out that, if you perform some manipulations/simplifications during the adjoint derivation including substitution of the N-S equations written on the surface, you arrive at an expression for the sensitivity that does not explicitly involve the pressure or stress tensor on the surface (please see Appendix E of "Continuous Adjoint Approach for the Spalart-Allmaras Model in Aerodynamic Optimization").

The surface sensitivity is computed for inviscid flows in CAdjEulerSolver::Inviscid_Sensitivity(CGeometry *geometry, CSolver **solver_container, CNumerics *numerics, CConfig *config) and for viscous flows in CAdjNSSolver::Viscous_Sensitivity(CGeometry *geometry, CSolver **solver_container, CNumerics *numerics, CConfig *config), which can both be found in the file solver_adjoint_mean.cpp in the latest version of the code.

Hope this helps, and cheers,
beatlejuice likes this.
economon is offline   Reply With Quote


force optimization, shape sensitivity

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Difference between pressure, absolute pressure and Total Pressure shaswat CFX 1 September 6, 2012 07:12
Dynamic pressure from the total pressure specified saisanthoshm88 CFX 1 August 9, 2012 07:13
Boundary Conditions : Total Pressure or Velocity Gearb0x OpenFOAM Running, Solving & CFD 2 February 28, 2011 22:18
rotating frame of reference and total pressure viking ANSYS 1 November 24, 2010 00:25
Total pressure in real gas (compressible flow) Bart Prast Main CFD Forum 3 November 14, 2000 11:44

All times are GMT -4. The time now is 17:56.