roberto marsilio - Academia.edu (original) (raw)

Uploads

Papers by roberto marsilio

Fluids, Dec 7, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

AIAA SCITECH 2023 Forum, Jan 19, 2023

34th AIAA Fluid Dynamics Conference and Exhibit, Jun 19, 2004

A Numerical technique to solve two-dimensional inverse problems that arise in aerodynamic design ... more A Numerical technique to solve two-dimensional inverse problems that arise in aerodynamic design is presented and discussed. The approach, which is well established for inviscid, rotational flows, is here extended to the viscous case. The solution of the inverse problem is given as the steady state of an ideal transient during which the flowfield assesses itself to the boundary conditions by changing the boundary contour. Comparison with theoretical and experimental results are used to validate the numerical procedure.

The reflectiveness of various boundary conditions is here investigated in the contest of Godunov ... more The reflectiveness of various boundary conditions is here investigated in the contest of Godunov methods and measured by an ad hoc introduced parameter τ. A new set of boundary conditions, for which is always τ = 0, i.e. totally non-reflecting is then proposed. The approach is also integrated in a novel procedure of aerodynamic design in the framework of a distributed boundary control based on the governing equations adjoint.

In this paper a numerical method for predicting the unsteady performances of an air-breathing eng... more In this paper a numerical method for predicting the unsteady performances of an air-breathing engine is presented. The flow around the nacelle and inside the engine ducts (e.g. air intakes, nozzles) is solved by CFD computations, while the flow evolution through compressor and turbine bladings are simulated via low order CFD models and actuator disks. Shaft work balance allows to derive the instantaneous rotor speed and to couple the fluid and engine dynamics. Without loss of generality, the methodology is explained assuming the turbojet as the reference engine

Computers & Fluids, Nov 1, 2012

A two-dimensional time-accurate numerical model to simulate complex reacting flowfields in chemic... more A two-dimensional time-accurate numerical model to simulate complex reacting flowfields in chemical non-equilibrium is presented. The aim of this study is to develop a computational tool which permits the analysis and the easy implementation of combustion phenomena for high speed flows. To construct an efficient numerical tool, while maintaining a reasonable accuracy, a semi-implicit numerical method was selected and verified for a hydrogen-air mixture. The numerical approach is based on a time-dependent, finite volume integration of the governing equations suitably modified for chemical non-equilibrium. The evaluation of the reacting constants based on Gibbs free energy and the Van't Hoff equation allows a very easy implementation of the chemical model used, regardless of its complexity. Calculations were performed with adeguate temporal and spatial resolution for modeling the physical process for practical calculation. Comparisons with numerical results are used for a verification of the numerical procedure.

52nd AIAA/SAE/ASEE Joint Propulsion Conference, Jul 22, 2016

The dynamic response of a Dual-Throat Nozzle in open and closed-loop control is investigate numer... more The dynamic response of a Dual-Throat Nozzle in open and closed-loop control is investigate numerically. Thrust vectoring in fixed, symmetric nozzles is obtained by secondary flow injections that cause local flow separations, asymmetric pressure distributions and the vectoring of primary jet flow. The computational technique is based on a model for the compressible URANS equations. A minimal control system governs the unsteady blowing. Nozzle performances and thrust vector angles have been computed for a wide range of nozzle pressure ratios and secondary flow injection rates. The numerical results are compared with the experimental data available in the open literature. Several computations of the open-loop dynamics of the nozzle under different forcing have been performed in order to investigate the system response in terms of thrust vectoring effectiveness and controllability. These computations have been used to extract ARX models of the nozzle dynamics. The effects of including the actuator dynamics are also discussed. Simple strategies of closed-loop control of the nozzle system by PID regulators are investigated numerically. The closed-loop Model Predictive Control of the system, based on the ARX models, is addressed

Fluid Dynamics Conference, Jun 19, 1995

Three-dimensional supersonic viscous laminar flows over symmetric corners are

Meccanica, Dec 1, 1989

ABSTRACT

Aerotecnica Missili & Spazio, Jul 1, 2016

The aim of this paper is to develop an axysimmetric numerical procedure, easily extendible to 3-D... more The aim of this paper is to develop an axysimmetric numerical procedure, easily extendible to 3-D configurations, based on the Reynolds averaged Navier-Stokes equations coupled with a turbulence model to compute the external flow of a plug nozzle. The governing equations are discretized in the physical domain according a finite-volume technique with second order accuracy. The turbulence equation written in integral form is solved together with the flow equations. Complex shock-slip surfaces, shock-boundarylayer interactions appear in the flowfield and all the flow discontinuities will be numerically captured.

Nucleation and Atmospheric Aerosols, 2022

International journal of turbomachinery, propulsion and power, Apr 21, 2021

2018 Joint Propulsion Conference, Jul 8, 2018

Computers & Fluids, Mar 1, 2006

A numerical technique to solve two-dimensional inverse problems that arise in aerodynamic design ... more A numerical technique to solve two-dimensional inverse problems that arise in aerodynamic design is presented. The approach, which is well established for inviscid, rotational flows, is here extended to the viscous case. Two-dimensional and axisymmetric configurations are here considered. The solution of the inverse problem is given as the steady state of an ideal transient during which the flowfield assesses itself to the boundary conditions by changing the boundary contour. Comparisons with theoretical and experimental results are used to validate the numerical procedure.

40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Jun 21, 2004

The aerodynamic design of classical and innovative nozzle concepts is investigated by an inverse ... more The aerodynamic design of classical and innovative nozzle concepts is investigated by an inverse method. The proposed numerical technique solves two-dimensional/axysimmetric viscous inverse problems that arise in aerodynamic design. The approach, which is well established for inviscid, rotational flows, is here extended to the viscous case. The methodology is coupled to an optimization technique seeking for wall pressure gradient distributions that maximize the nozzle thrust.

The aerospike nozzle represents an interesting technology for Single-Stage-To-Orbit vehicles beca... more The aerospike nozzle represents an interesting technology for Single-Stage-To-Orbit vehicles because of its self-adapting capability. It is possible to get thrust vectoring capabilities in different ways. A straightforward solution consists in applying differential throttling to multiple combustion chambers which feed the nozzle. An alternative technology, which can be used in the presence of a common combustion chamber, is represented by fluidic thrust vectoring which requires the injection of a secondary flow from a slot on the wall. In this work, the flow field in a linear aerospike nozzle is numerically investigated by means of RANS simulations and both differential throttling and shock vectoring are studied. A parametric study is performed to evaluate the potential of the two technologies.