Numerical Platform

Computational physics plays the prime role at the present stage of R&D: coupled complex multi-physics interdisciplinary simulations are based on the computational fluid dynamics (CFD), computational aero-acoustics (CAA), combustion and heat- and mass transfer, multi-phase flows and high performance computing (HPC).

The numerical platform is based on the finite-volume method of the 2nd order approximation in space and time coupled withe the conventional Reynolds-Averaged Navier-Stokes (RANS) approach as well as Large-Eddy Simulation (LES) implemented in the open source OpenFOAM® toolbox. The platform contains four main blocks to cover:

• turbulent flows at low Mach numbers (M < 0.3);
• transonic and supersonic flows (M < 5) at high Reynolds numbers;
• inert and reactive simulations for unsteady combustion physics;
• tools for the spectral analysis, machine learning and flow control algorithms.

Turbulent separated and bluff-body flows

The turbulent, separated flows past bluff-bodied play a significant role in external aerodynamic applications. During the last several decades the detailed validation and verification studies have been performed for simple geometries (like circular, square, triangular and semicircular cylinders) to assess different numerical and experimental methods to investigate the flow physics, wake dynamics and basic integral and local flow parameters.

During the last decade the present numerical platform was proven as an accurate and efficient tool to investigate the turbulent separated flows at the moderate Reynolds numbers:

• Lysenko et al., Flow Turbul. Combust. (2012);
• Lysenko et al., Comput. Fluids (2013);
• Lysenko et al., Flow Turbul. Combust. (2014);
• Prsic et al., Ocean Eng (2014);
• Cao and Tamura, J. Fluids Struct. (2015);
• Robertson et al., Comput. Fluids (2015);
• Cao & Tamura, Comput. Fluids (2016);
• Lysenko et al., Flow Turbul. Combust. (2018);
• Jin et al., Ocean Eng (2019)
• Zahiri & Roohi, Comput. Fluids (2019);
• Lysenko et al., Comput. Fluids (2021);
• Lysenko et al., Ocean Eng. (2021).

Transonic and supersonic flows

The related ongoing topics of research are:
• The ƛ-shock formation associated with planar, transonic flows past bluff-bodies of various shapes;
• Unsteady physics of the separated shockwave-boundary interaction (SBLI) including the turbulence genesis, the high-amplitude, low-frequency unsteadiness and its passive control.

The novel super-fast, hybrid CPU-GPU framework to simulate planar compressible flows based on Julia HPC language.

Inert and reactive simulations (combustion)

edcPimpleFoam is a state-of-the-art, all Mach number solver for the turbulent combustion modeling (non-premixed and premixed) ans simulations, which incorporates the conventional Reynolds-averaged formulation (unsteady RANS) and the Large-Eddy Simulation (LES) model. The Eddy Dissipation Concept with a detailed chemistry approach is used for the turbulence-chemistry interaction. A robust implicit Runge-Kutta method (RADAU5) for integrating stiff ordinary differential equations allows to calculate chemical systems of any type of complicity. All these features allow to simulate the unsteady combustion physics in very accurate and efficient manner.

Spectral analysis, machine learning and flow control

Novel breakthrough algorithms for active and passive flow control based on the superposition of Machine learning | Evolutionary biology | Generalized physics and Computational fluid dynamics.

The spectral analysis of the bluff-body wakes dynamics is of high importance for the project as well. For this purpose a fast Fourier transform (FFT), continues wavelet transform (CWT) and Lyapunov stability theory, based on Julia HPC language, have been adopted and verified intensively.