Jochen Fröhlich

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An efficient approach for the simulation of finite-size particles with interface resolution was presented by Uhlmann (J. Comput. Phys, Vol. 209, pp. 448-476, 2005). The present paper proposes several enhancements of this method which considerably improve the results and extend the range of applicability. An important step is a simple low-cost iterative(More)
Three cases of variable-density turbulent round jets discharging from a straight circular pipe into a weakly confined low-speed co-flowing air stream are studied with the aid of large eddy simulation. The density ratios considered are 0.14 [He/air], 1.0 [air/air] and 1.5 [CO2/air], with Reynolds numbers of 7000, 21000 and 32000, respectively. Detailed(More)
therefore the damping layer has to be large enough to prevent reentrant waves at the physical boundary. Hence In this paper we develop a method for the simulation of wave propagation on artificially bounded domains. The acoustic wave the approach is not only costly in terms of memory requireequation is solved at all points away from the boundaries by a(More)
The two-sample Wilcoxon rank sum test is the most popular non-parametric test for the comparison of two samples when the underlying distributions are not normal. Although the underlying distributions need not be known in detail to calculate the null distribution of the test statistic, parametric assumptions are often made to determine the power of the test(More)
High-order methods gain more and more attention in computational fluid dynamics. However, the potential advantage of these methods depends critically on the availability of efficient elliptic solvers. With spectralelement methods, static condensation is a common approach to reduce the number of degree of freedoms and to improve the condition of the(More)
• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the(More)
We present Multilevel Finite Element computations for twodimensional reaction-diffusion systems modelling laminar flames. These systems are prototypes for extreme stiffness in time and space. The first of these two rather general features is accounted for by an improved control mechanism for the time step. The second one is reflected through very thin(More)
The flow around an arrangement of two-in-tandem cylinders exhibits a remarkably complex behaviour that is of interest for many engineering problems, such as environmental flows or structural design. In the present paper, a Large Eddy Simulation using a staggered Cartesian grid has been performed for the flow around two-in-tandem cylinders of diameter D=20mm(More)
We construct an orthogonal wavelet basis for the interval using a linear combination of Legendre polynomial functions. The coefficients are taken as appropriate roots of Chebyshev polynomials of the second kind, as has been proposed in reference [1]. A multi-resolution analysis is implemented and illustrated with analytical data and real-life signals from(More)
Combustion is and for the foreseeable future will be the major source for the production of mechanical and electrical energy. Currently, more than 90% of primary energy are generated through combustion [1]. According to the World Energy Council the energy demand will increase by 65% until 2020. Against this background it is of primordial interest to make(More)