Turbulent flows

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CURRENT RESEARCH TOPICS

Wall Modelled Large Eddy Simulation

Collaborators: Francesco De Vanna, Michele Cogo and Prof. Francesco Picano, Prof. Matteo Bernardini (Sapienza) and Prof. Ernesto Benini.

Large-eddy-simulation is a promising strategy for turbulent flow simulation in applications. However, a very fine mesh is required near the wall (wall-resolved) for reliable results, so wall-modelled methods have been developed to reduce the computational cost. We are developing efficient algorithms to provide the best wall treatment for different flow conditions (e.g. attached vs separated flows). Our methodology has been tested in incompressible and compressible turbulent channels and boundary layers with good results.

Reference(s):

  • F De Vanna, M Cogo, M Bernardini, F Picano, E Benini, Unified wall-resolved and wall-modeled method for large-eddy simulations of compressible wall-bounded flows, Physical Review Fluids 6 (3), 034614, 2021

Reentry capsule on Mars atmosphere

Collaborators: Luca Placco, Michele Cogo, Prof. Francesco Picano and Prof. Matteo Bernardini (Sapienza).

Entry and descent phases of an interplanetary probe are characterized by complex aerodynamic phenomena as the capsule gradually encounters the planet’s atmosphere. We are conducting time-evolving high-fidelity simulations of an entry capsule in a supersonic flight regime (Ma = 2), evaluating its behaviour at different configurations of angles of attack. Turbulent structures effectively solved via ILES technique, allow us to evaluate the flow properties and the capsule’s response both in space and time, placing special attention to the analysis of the turbulent structures responsible for the oscillatory and unsteady dynamics.

Direct numerical simulation of hypersonic boundary layers at high Reynolds numbers

Collaborators:  Michele Cogo, Francesco Salvadore (CINECA), Prof. Francesco Picano and Prof. Matteo Bernardini (Sapienza).

To design the new generation of high-speed aircraft and re-entry vehicles, it is essential to predict the drag and heat flux generated at the boundary of the vehicle, where boundary layers are present. However, the classical theories, from which lots of engineering models are developed, are not able to handle high thermal fluxes at the solid boundaries and intense pressure waves, which increase considerably at high-Mach numbers. We are conducting numerical studies using Direct Numerical Simulation at different Mach and Reynolds number to gauge the effect that these parameters have on the instantaneous and statistical properties of the flow.