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- Martin Berggren
- SIAM J. Scientific Computing
- 1998

In order to laminarize an unsteady, internal flow, the vorticity field is minimized, in a least-squares sense, using an optimal-control approach. The flow model is the Navier–Stokes equation for a viscous incompressible fluid, and the flow is controlled by suction and blowing on a part of the boundary. A quasi-Newton method is used for the minimization of a… (More)

Shape optimization of an acoustic horn is performed with the goal to minimize the portion of the wave that is reflected. The analysis of the acoustical properties of the horn is performed using a finite element method for the Helmholtz equation. The optimization is performed employing a BFGS Quasi-Newton algorithm, where the gradients are provided by… (More)

- Martin Berggren
- SIAM J. Numerical Analysis
- 2004

Standard weak solutions to the Poisson problem on a bounded domain have squareintegrable derivatives, which limits the admissible regularity of inhomogeneous data. The concept of solution may be further weakened in order to define solutions when data is rough, such as for inhomogeneous Dirichlet data that is only square-integrable over the boundary. Such… (More)

- Eddie Wadbro, Martin Berggren
- SIAM Review
- 2009

- C Y-C Wu, Jörg C. Sturm, +113 authors R Quake
- 2003

C%D ! # ' F # 9 . ) . F + / " %3?G ! H H @ " 0 / H = ) > I J H %3*% ! # ' 9 ) 6 9 0 # @ # (?%& C3D > , # : . , > ) F # # + : + ) # , ' , (4G C(D 6 # 2 : H + , . @ > = 3-$ C*D K : / . . F # 0 / : # , ) F @ $-% C$D / / : , # L ) + 9 / . : # , 6 9 2 ) F @ %(*G C?D . : 9 H L ' M , L @ F L ) F ! 4$-G C4D ! @ 9 ) + > # . @ > : ) @ 0 > # F / 2 6 = . " ! 3%33 ! , 9… (More)

- Eddie Wadbro, Rajitha Udawalpola, Martin Berggren
- J. Computational Applied Mathematics
- 2010

Using gradient-based optimization combined with numerical solutions of the Helmholtz equation, we design an acoustic device with high transmission efficiency and even directivity throughout a two-octave-wide frequency range. The device consists of a horn, whose flare is subject to boundary shape optimization, together with an area in front of the horn,… (More)

We use a gradient-based material distribution approach to design conductive parts of microstrip antennas in an efficient way. The approach is based on solutions of the 3D Maxwell’s equation computed by the finite-difference time-domain (FDTD) method. Given a set of incoming waves, our objective is to maximize the received energy by determining the… (More)

- Eddie Wadbro, Martin Berggren
- SIAM J. Scientific Computing
- 2008

- O. Amoignon, Martin Berggren
- 2005

The sensitivity analysis is a crucial step in algorithms for gradient-based aerodynamic shape optimization. The analysis involves computing the gradient of functionals such as drag, lift, or aerodynamic moments, with respect to the parameters of the design. Gradients are efficiently calculated by solving adjoints of the linearized flow equations. The flow… (More)

A Topology optimization technique is used for complete layout optimization of the radiating element of a planar monopole antenna. The design objective is to find a conductivity distribution that maximizes the energy received by the planar monopole over the frequency band 1-10 GHz. The finite difference time domain method (FDTD) is used for the numerical… (More)