Computational fluid dynamics is employed to predict the aerodynamic properties of the prototypical trailing-edge control surfaces for a small, regional transport, commercial aircraft. The virtual experiments are performed at operational flight conditions, by resolving the mean turbulent flow field around a realistic model of the whole aircraft. The Reynolds-averaged Navier–Stokes approach is used, where the governing equations are solved with a finite volume-based numerical method. The effectiveness of the flight control system, during a hypothetical conceptual pre-design phase, is studied by conducting simulations at different angles of deflection, and examining the variation of the aerodynamic loading coefficients. The proposed computational modeling approach is verified to have good practical potential, also compared with reference industrial data provided by the Leonardo Aircraft Company.

Computational Evaluation of Control Surfaces Aerodynamics for a Mid-Range Commercial Aircraft

This article represents the natural continuation of the work by Rossano and De Stefano (2021), dealing with the computational fluid dynamics analysis of a shock wave interaction with a liquid droplet. Differently from our previous work, where a two-dimensional approach was followed, fully three-dimensional computations are performed to predict the aerodynamic breakup of a spherical water body due to the impact of a traveling shock wave. The present engineering analysis focuses on capturing the early stages of the breakup process under the shear-induced entrainment regime. The unsteady Reynolds-averaged Navier–Stokes approach is used to simulate the mean turbulent flow field in a virtual shock tube device with circular cross section. The compressible-flow-governing equations are numerically solved by means of a finite volume method, where the volume of fluid technique is employed to track the air–water interface. The proposed computational modeling approach for industrial gas dynamics applications is verified by making a comparison with reference numerical data and experimental findings, achieving acceptably accurate predictions of deformation and drift of the water body without being computationally cumbersome.

/pdf/computational-evaluation-of-shock-wave-interaction-with-a-187locyv.pdf

Computational Evaluation of Shock Wave Interaction with a Liquid Droplet

Computational fluid dynamics was employed to predict the early stages of the aerodynamic breakup of a cylindrical water column, due to the impact of a traveling plane shock wave. The unsteady Reynolds-averaged Navier–Stokes approach was used to simulate the mean turbulent flow in a virtual shock tube device. The compressible flow governing equations were solved by means of a finite volume-based numerical method, where the volume of fluid technique was employed to track the air–water interface on the fixed numerical mesh. The present computational modeling approach for industrial gas dynamics applications was verified by making a comparison with reference experimental and numerical results for the same flow configuration. The engineering analysis of the shock–column interaction was performed in the shear-stripping regime, where an acceptably accurate prediction of the interface deformation was achieved. Both column flattening and sheet shearing at the column equator were correctly reproduced, along with the water body drift.

Computational Evaluation of Shock Wave Interaction with a Cylindrical Water Column

A hybrid VOF–Lagrangian method for simulating the aerodynamic breakup of liquid droplets induced by a traveling shock wave is proposed and tested. The droplet deformation and fragmentation, together with the subsequent mist development, are predicted by using a fully three-dimensional computational fluid dynamics model following the unsteady Reynolds-averaged Navier–Stokes approach. The main characteristics of the aerobreakup process under the shear-induced entrainment regime are effectively reproduced by employing the scale-adaptive simulation method for unsteady turbulent flows. The hybrid two-phase method combines the volume-of-fluid technique for tracking the transient gas–liquid interface on the finite volume grid and the discrete phase model for following the dynamics of the smallest liquid fragments. The proposed computational approach for fluids engineering applications is demonstrated by making a comparison with reference experiments and high-fidelity numerical simulations, achieving acceptably accurate results without being computationally expensive.

/pdf/hybrid-vof-lagrangian-cfd-modeling-of-droplet-aerobreakup-hnnxcnfi.pdf

Hybrid VOF–Lagrangian CFD Modeling of Droplet Aerobreakup

Abstract In the aircraft industry, the ultimate goal in any component’s design is to minimize its weight, maximize its durability, and increasing its life while keeping its overall life cycle costs low. As technology is progressing, UCAVs are gaining more and more prominence as jet powered UCAVs are already taking to skies presenting a myriad of challenges. This is especially true in the case of Landing gears as greater crashworthiness is required in high-speed high payload UCAVs. As jet powered UCAVs have a higher touchdown velocity and thus a higher chance of failure. In this research, a category of unmanned combat aerial vehicles was picked. In that category, a number of reference unmanned combat aerial vehicles were selected to extract the required parameters and dimensions of their main landing gears from literature review and analysis. The main landing gear was then modeled in CAD. Simultaneously loading conditions were defined and loads were determined. The equivalent von mises and maximum principal stresses were obtained from finite element analysis for multiple materials using the finite element package ANSYS. These results were then in turn used to calculate the factor of safety. Furthermore, an impact analysis was carried out in this crashworthiness study using Explicit Dynamics in LS DYNA for the same material. The stress formulations and deformations in impact were highly non-linear and more realistic and accurate than in static structural. The results were then validated.

Crashworthiness study of UCAV’s main landing gear using explicit dynamics

Computational fluid dynamics is employed to evaluate the mean aerodynamic loading on the retractable landing-gears of a regional transport commercial aircraft. The mean turbulent flow around simplified landing-gear systems including doors is simulated by using the Reynolds-averaged Navier–Stokes approach, where the governing equations are solved with a finite volume-based numerical method. Using a dynamic meshing method, the computational grid is automatically and continuously adapted to the time-changing geometry, while following the extension/retraction of the landing-gear systems. The temporal evolution of the aerodynamic forces on both the nose and the main landing-gears, along with the hinge moments of the doors, is numerically predicted. The proposed computational modeling approach is verified to have good practical potential when compared with reference experimental data provided by the Leonardo Aircraft structural loads group.

https://www.mdpi.com/2226-4310/7/6/68/pdf

Computational Evaluation of Aerodynamic Loading on Retractable Landing-Gears

CFD analysis is carried out to evaluate the mean aerodynamic loads on the retractable main landing-gear of a regional transport commercial aircraft. The mean flow around the landing-gear system including doors is simulated by using the Reynolds-averaged Navier-Stokes modelling approach, the governing equations being solved with a finite volume-based numerical technique. The computational grid is automatically adapted to the time-changing geometry by means of a dynamic meshing technique, while following the deployment of the landing-gear system. The present computational modelling approach is verified to have good practical potential by making a comparison with reference experimental data provided by the Leonardo Aircraft Company aerodynamicists.

CFD Prediction of Retractable Landing Gear Aerodynamics

The effectiveness of prototypical control surfaces for a modern regional transport commercial aircraft is examined by means of numerical simulations. The virtual experiments are performed in operational conditions by resolving the mean turbulent flow field around a suitable model of the whole aircraft. The Reynolds-averaged Navier-Stokes modelling approach is used, where the governing equations are solved with a finite volume-based numerical technique. The aerodynamic performance of the flight control surfaces, during an hypothetical conceptual design phase, is evaluated by conducting simulations at different deflections. The present computational modelling approach is verified to have good practical potential by making a comparison with reference industrial data.

Antonio Piccolo

Papers

Computational Evaluation of Aerodynamic Loading on Retractable Landing-Gears

Computational Evaluation of Control Surfaces Aerodynamics for a Mid-Range Commercial Aircraft

CFD Prediction of Retractable Landing Gear Aerodynamics

CFD Prediction of Aircraft Control Surfaces Aerodynamics