BAIL 2006 Book of Abstracts - Institut für Numerische und ...

BAIL 2006 Book of Abstracts - Institut für Numerische und ... BAIL 2006 Book of Abstracts - Institut für Numerische und ...

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R. HARTMANN: Discontinuous Galerkin methods for compressible flows: higher order accuracy, error estimation and adaptivity ✬ ✫ Discontinuous Galerkin methods for compressible flows: higher order accuracy, error estimation and adaptivity Ralf Hartmann Institute of Aerodynamics and Flow Technology, German Aerospace Center (DLR), Lilienthalplatz 7, 38108 Braunschweig, Germany The Discontinuous Galerkin (DG) method for the compressible Euler equations is extended to the symmetric interior penalty (SIP)DG method for the compressible Navier-Stokes equations, see Hartmann & Houston [2]. Shock-capturing is used to avoid overshoots near shocks, see Hartmann [1]. The nonlinear equations are solved using a fully implicit solver. We demonstrate the accuracy of higher order DG discretizations with respect to the approximation of aerodynamical force coefficients and to the approximation of viscous boundary layers, see Figure 1 and Hartmann & Houston [2]. Finally, we demonstrate the use of a posteriori error estimation and goal-oriented (also called weighted-residual-based or adjoint-based) adaptive mesh refinement for subsonic flows, Hartmann & Houston [3], and for supersonic compressible flows, see Figure 2 and Hartmann [1]. References [1] R. Hartmann. Adaptive discontinuous Galerkin methods with shock-capturing for the compressible Navier-Stokes equations. Int. J. Numer. Meth. Fluids, 2006. To appear. [2] R. Hartmann and P. Houston. Symmetric interior penalty DG methods for the compressible Navier–Stokes equations I: Method formulation. Int. J. Num. Anal. Model., 3(1):1–20, 2006. [3] R. Hartmann and P. Houston. Symmetric interior penalty DG methods for the compressible Navier–Stokes equations II: Goal–oriented a posteriori error estimation. Int. J. Num. Anal. Model., 3(2):141–162, 2006. Speaker: HARTMANN, R. 22 BAIL 2006 1 ✩ ✪

R. HARTMANN: Discontinuous Galerkin methods for compressible flows: higher order accuracy, error estimation and adaptivity ✬ ✫ c dp 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 reference cdp DG(3), global refinement DG(2), global refinement DG(1), global refinement 10000 100000 number of elements |c dp − 0.0222875| 0.01 0.001 0.0001 (a) (b) DG(1), global refinement DG(2), global refinement DG(3), global refinement 10000 100000 number of elements Figure 1: Subsonic laminar flow around the NACA0012 airfoil at M = 0.5, α = 0 and Re = 5000: Convergence of the pressure induced drag cdp under global refinement for DG(p), p = 1,2,3: (a) cdp versus number of elements; (b) Error in cdp (reference cdp − cdp) versus number of elements. For more detail cf. Hartmann & Houston [2]. 8 4 0 -4 -8 -4 0 4 8 8 4 0 -4 -8 -4 0 4 8 (a) (b) Figure 2: Supersonic laminar flow around the NACA0012 airfoil at M = 1.2, α = 0 and Re = 1000: (a) Residual-based refined mesh of 17670 elements with 282720 degrees of freedom and |Jcdp (u) − Jcdp (uh)| = 1.9 · 10 −3 ; (b) Adjoint-based refined mesh for cdp: mesh of 10038 elements with 160608 degrees of freedom and |Jcdp (u) − Jcdp (uh)| = 1.6 · 10 −4 . For more detail cf. Hartmann [1]. Speaker: HARTMANN, R. 23 BAIL 2006 2 ✩ ✪

R. HARTMANN: Discontinuous Galerkin methods for compressible flows: higher order<br />

accuracy, error estimation and adaptivity<br />

✬<br />

✫<br />

Discontinuous Galerkin methods for compressible flows:<br />

higher order accuracy, error estimation and adaptivity<br />

Ralf Hartmann<br />

<strong>Institut</strong>e <strong>of</strong> Aerodynamics and Flow Technology, German Aerospace Center (DLR),<br />

Lilienthalplatz 7, 38108 Braunschweig, Germany<br />

The Discontinuous Galerkin (DG) method for the compressible Euler equations is extended<br />

to the symmetric interior penalty (SIP)DG method for the compressible Navier-Stokes equations,<br />

see Hartmann & Houston [2]. Shock-capturing is used to avoid overshoots near shocks, see Hartmann<br />

[1]. The nonlinear equations are solved using a fully implicit solver. We demonstrate the<br />

accuracy <strong>of</strong> higher order DG discretizations with respect to the approximation <strong>of</strong> aerodynamical<br />

force coefficients and to the approximation <strong>of</strong> viscous bo<strong>und</strong>ary layers, see Figure 1 and<br />

Hartmann & Houston [2].<br />

Finally, we demonstrate the use <strong>of</strong> a posteriori error estimation and goal-oriented (also<br />

called weighted-residual-based or adjoint-based) adaptive mesh refinement for subsonic flows,<br />

Hartmann & Houston [3], and for supersonic compressible flows, see Figure 2 and Hartmann [1].<br />

References<br />

[1] R. Hartmann. Adaptive discontinuous Galerkin methods with shock-capturing for the compressible<br />

Navier-Stokes equations. Int. J. Numer. Meth. Fluids, <strong>2006</strong>. To appear.<br />

[2] R. Hartmann and P. Houston. Symmetric interior penalty DG methods for the compressible<br />

Navier–Stokes equations I: Method formulation. Int. J. Num. Anal. Model., 3(1):1–20, <strong>2006</strong>.<br />

[3] R. Hartmann and P. Houston. Symmetric interior penalty DG methods for the compressible<br />

Navier–Stokes equations II: Goal–oriented a posteriori error estimation. Int. J. Num. Anal.<br />

Model., 3(2):141–162, <strong>2006</strong>.<br />

Speaker: HARTMANN, R. 22 <strong>BAIL</strong> <strong>2006</strong><br />

1<br />

✩<br />

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