Daniel Lindblad

CFD Software Entwicklungs- und Forschungsgesellschaft GmbH

In this paper we couple the Ffowcs - Williams & Hawkings (FW-H) method with a regularized Boundary Element Method (BEM) to compute noise scattering against solid bodies. The benefit of the chosen approach is that the computation of the noise sources, which is typically done with high-fidelity CFD/CAA, is decoupled from the noise scattering problem....

Scale-resolving simulations are used to study jet-wing installation noise for a 1:19 scale model of a realistic short-to-medium range aircraft equipped with ultra-high bypass ratio turbofan engines. To this end, a convective version of the Curle integral is used to study the directivity of the installation noise. For matter of completeness, the res...

In this work, the open-source spectral/hp element framework Nektar++ is coupled with the Antares library to predict noise from a subsonic jet. Nektar++ uses the high-order discontinuous Galerkin method to solve the compressible Navier-Stokes equations on unstructured grids. Unresolved turbulent scales are modeled using an implicit Large Eddy Simula...

The harmonic balance method has emerged as an efficient and accurate approach for computing periodic, as well as almost periodic, solutions to nonlinear ordinary differential equations. The accuracy of the harmonic balance method can however be negatively impacted by aliasing. Aliasing occurs because Fourier coefficients of nonlinear terms in the g...

The design of noise barriers for high-speed trains is challenging due to the flow interaction between the train body and barriers. A failed design could affect the flow that in turn introduces additional aerodynamic loads to the train and generates extra noise. This study is the first investigation to numerically explore the detailed effects of noi...

The harmonic balance method is nowadays widely applied for numerically solving problems that are known to possess time-periodic solutions. Key reasons for its success are its wide range of applicability, relative ease of implementation, and computational efficiency compared to time-accurate approaches. The computational efficiency of the harmonic b...

Higher order nonreflecting blade row interfaces are today widely used for performing both steady and unsteady simulations of the flow within axial turbomachines. In this paper, a quasi-three-dimensional nonreflecting interface based on the exact, two-dimensional nonreflecting boundary condition for a single frequency and azimuthal wave number devel...

The Counter Rotating Open Rotor (CROR) powerplant is an interesting architecture for future regional aircraft propulsion since it offers higher propulsive efficiency and thereby lower fuel consumption than the conventional Turbofan engine. The noise levels generated are however potentially larger compared to a Turbofan due in part to the absence of...

A computational method for predicting turbomachinery tonal noise is presented. It is based on the Harmonic Balance method, which solves for the dominant frequencies of the flow generated by bladerow interaction. Coupling between the resolved frequencies is furthermore enabled since the Harmonic Balance method is applicable to the nonlinear Euler or...