A large number of available computational fluid dynamics codes include tools for analysis of computational aeroacoustics problems. Such tools are proprietary as well as the codes themselves. Actually, the level of development of such codes as OpenFOAM makes it possible to implement enough opportunities for complication of physical models and increasing the scale of the issues described. In our paper, we develop a dynamic library libAcoustics which may be compiled independently of any modules of the main OpenFOAM package and the type of solvers being used in the model. The implemented Curle's analogy in library makes it possible to obtain acoustic spectra under the conditions of turbulent flows around arbitrary solids in a medium moving at a low velocity of flow. Calculation of the acoustic field was made for 3D test case of Cylinder – NACA 0012 Wing Profile configuration. The analogy allows user to define solvers settings through standard user I/O dictionaries of the OpenFOAM. A complete implementation of the analogy is capable of producing parallel computation. The libAcoustics library is free and is available for download on demand

The paper presents a brief review of computational approaches for the simulation of turbulent flows and shows that the correct calculation of large-scale vortex structures necessarily requires the use of eddy-resolving methods, while the applied numerical schemes must be stable and accurately describe the spatial evolution of vortices. The dissipative properties and stability of most numerical schemes implemented in the OpenFOAM package are analyzed by solving problems on the decay of the homogeneous isotropic turbulence and scalar transfer. It is established that the considered schemes are not suitable for correctly calculating the propagation and dissipation of vortices in space; therefore, they are refined to eliminate oscillations and maintain an acceptable level of dissipation. An algorithm for combining the URANS and LES methods using zoning of the computational domain is described and implemented. To test the implemented calculation method of unsteady turbulent flows, we simulate the flow around a maneuvering aircraft with an installed airbrake deflection. The flow patterns of the aircraft and its aerodynamic characteristics are obtained and compared with the experimental data.

This paper presents the Eulerian–Lagrangian approach for numerical modeling of high-speed gas-droplet flows and aeroacoustics. The proposed hybrid approach is implemented using the OpenFOAM library and two different methods. The first method is based on a hybrid convective terms approximation method employing a Kurganov–Tadmor and PIMPLE scheme. The second method employs the regularized or quasi-gas dynamic equations. The Lagrangian part of the flow description uses the OpenFOAM cloud model. Within this model, the injected droplets are simulated as packages (parcels) of particles with constant mass and diameter within each parcel. According to this model, parcels moving in the gas flow could undergo deceleration, heating, evaporation, and breakup due to hydrodynamic instabilities. The far-field acoustic noise is predicted using Ffowcs Williams and Hawking’s analogy. The Lagrangian model is verified using the cases with droplet evaporation and motion. Numerical investigation of water microjet injection into the hot ideally expanded jet allowed studying acoustic properties and flow structures, which emerged due to the interaction of gas and liquid. Simulation results showed that water injection with a mass flow rate equal to 13% of the gas jet mass flow rate reduced the noise by approximately 2 dB. This result was in good coincidence with the experimental observations, where maximum noise reduction was about 1.6 dB.

The paper presented the specifics of calculating the characteristics of vortex propagation and decay processes which cause aerodynamic tail fin-buffet loads in an aircraft at incompressible subsonic flow. Analysis of numerical diffusion and stability of differencing schemes implemented in OpenFOAM software package has been carried out. Based on the obtained results, differencing schemes are selected and their modification has been done. An algorithm has been presented for combining various approaches for modelling turbulent flows (RANS-LES) by means of zonal isolation and its implementation in OpenFOAM package is carried out. A series of calculations of three-dimensional flow around an aircraft at angles of attack of 0 to 30 degree considering airbrake deflections on 60 degree are conducted. Flow separation at the airbrake side edges and upper edge result in a highly turbulent wake. The corresponding region of vortex flow affects the fin and causes buffet loads.

Two modal decomposition techniques, including proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD), were used to identify the wake patterns past single and two crossing cylinders in 60° and 90° arrangements with gap ratio G = 4. The flow was simulated using direct numerical simulations (DNS) for Reynolds numbers Re = 100. From modal analysis, the flow’s spatial scale decreased with increasing modal frequency. Two main modes were identified in the wake of the cylinders, namely spatially antisymmetric and symmetric modes. Antisymmetric and symmetric modes were related to the cylinders’ vortex shedding and shedding vortices’ shift motion, respectively, whose frequencies were odd and even multiples of the cylinders’ lift force frequency. In addition, a low-frequency mode concerning the shadowing effect of the downstream cylinder (DC) in 90° arrangement was found in the wake of the DC centre.

The paper presents an analysis of various approaches for calculation gas-dynamic parameters and acoustic perturbations generated by a compressible jet at low Reynolds number (M = 0.9, Re = 3600). The jet flow parameters at selected conditions are well studied and can be used for validation of the numerical methods and schemes. The OpenFOAM software package with various approaches (solvers) such as pimpleCentralFoam, dbnsTurbFoam and new QGDFoam solver based on QGD-algorithms are considered. The results of time-averaged flow parameters and acoustic properties are compared with the experimental data. To determine the acoustic perturbation the Ffowcs Williams and Hawkings analogy implemented in our OpenFOAM library (libAcoustic) has been used.