Previously, the prediction of jet mixing noise from hot and cold isolated nozzle configurations has been studied with the means of RPM (Random Particle M esh) method using the Tam & Auriault or rather Tam, Pastouchenko and Viswanathan source model. The acoustical sources are generated as a reproduction of experimentally observed two-point cross-correlation functions using as input the turbulence statistics from RANS data. The sound propagation and extrapolation are performed with the linearized Euler equations in the near-field and with the Ffowcs-Williams & Hawkings method in the far-field. Efficient CAA computations are achieved exploiting the advantage of Fourier series decomposition for isolated axisymmetric and quasi-axisymmetric nozzle geometries. For investigation of installation effects the azimuthal-modal approach is however not applicable due to highly three-dimensional flow interactions, e.g. if a jet engine is mounted below an airfoil. Therefore, in contrast to the isolated nozzle configurations, in this case the resolution of computational domain in all three spatial dimensions is needed. Next to the RPM method, which is solely capable to generate two-dimensional acoustical sources, the FRPM method is available that is able to generate both, 2-D and 3-D sources. First test computations with FRPM method were conducted for a single stream jet, whereas the azimuthal-modal results of RPM were used as reference solution. The installed jet configurations are subsequently studied building on the FRPM computations of the single stream jet.

A highly loaded compressor cascade is analyzed by means of time-resolved 3D RANS simulations. Due to the low aspect ratio of the cascade, strong three-dimensional effects emerge, such as large corner vortices and trailing edge separation at the midspan. The feasibility of the simulation using a commercial software and the applicability of controlling the separated regions using zero net mass flux synthetic jets is analyzed. The work includes two control concepts that are investigated separately. One aims to affect the secondary flow emerging from the sidewalls via actuation at the cascade casing walls. The other aims to reattach the separated flow to the blade suction side using an actuator on the blade. Beneficial flow control parameters characterizing a synthetic jet are determined for both locations by a systematic variation. Special attention is drawn to the global efficiency of the stator cascade by means of total pressure loss and pressure rise.

Time-resolved Reynolds-Averaged Navier-Stokes simulations of a 3D stator compressor cascade are performed. At the design point of the airfoil under investigation, pronounced secondary flow effects are observed. Strong corner vortices emerge from the casing walls and the flow separates from the blade suction side towards the trailing edge. Transition from laminar to turbulent flow occurs within a laminar separation bubble. Using a commercial CFD software, the influence of the spatial resolution is investigated by means of a spanwise coarsening and refinement of the created mesh. Zero net mass flux synthetic jet actuation is used to control the separated regions. The work presents a variation of the temporal discretization and an analysis of the driving parameters of the actuation.

It is shown in a simulation that the tonal sound emission of a high-pressure turbine stage may increase considerably when the mean temperature of the inflow is spatially not uniform. The tonal sound power emitted in the downstream direction is increased by 5.9 dB at the blade passing frequency fb and by 11.7 dB at 2fb. The mean total temperature of the incoming flow is assumed to vary periodically in the azimuthal direction with a temperature amplitude of ±9% as a result of 14 discrete burners inside the annular combustion chamber. The temperature also varies radially with minima at the inner and outer walls of the annular channel. The turbine stage consists of a stator with 70 vanes and a rotor with 73 blades, while the temperature field in the simulation has 14 periods in the circumference.

Further development and validation of an innovative DES-based methodology for the prediction of jet noise from installed configurations is presented. A Grey-Area improved Delayed Detached-Eddy Simulation (DDES) model has been implemented in an industrial solver and validated for a static single-stream jet. The measured far-field sound directivity was predicted to within 2 dB and frequencies up to around St = 2 to 3 were resolved on a grid of 15.4M cells. To address the key problem of defining a suitable location of the data surface for Ffowcs Williams & Hawkings (FWH) far-field integration, a sensor function based on a statistical evaluation of the vorticity magnitude is proposed. This is applied to a complex installed jet/wing configuration, for which predicted far-field noise levels are shown. A strong increase in noise due to the presence of the wing of up to 18 dB in the forward arc is reported. This interaction noise becomes stronger and shifts to higher frequencies when the wing is moved closer to the jet.