Stability, Flying Qualities and Parameter Estimation of a Twin-Engine CS23/FAR23 Certified Light Aircraft

This paper presents some results of the flight test campaign conducted on the Tecnam P2006T aircraft, on the occasion of its certification process. This twin-engine propeller airplane is certified in the category CS23/FAR23. Many preliminary flight tests on a prototype of this light aircraft were aimed at optimizing performances and flight qualities. These experiences led to the application of two winglets to the original wing. The final configuration was extensively tested for the purpose of CS23 certification achievement. At the same time the airplane model, through a dedicated set of flight maneuvers, has been characterized by means of parameter estimation studies. The longitudinal and lateral-directional response mode were assessed and quantified. All the aircraft stability derivatives have been estimated from the acquired flight data using the well-known Maximum Likelihood Method (MLM). Some estimated stability derivatives have been also compared with the corresponding values extracted from leveled flight tests and from wind-tunnel tests performed on a scaled model of the aircraft

Glueballs and topology with O(a)-improved lattice QCD

We present evidence for unquenching effects in N_f=2, 16^3 32 ensembles by comparing with `equivalent' quenched data at r_0~5.0. A (small) VEV for torelons signals (weak) string breaking. A 15-20 % reduction in the scalar glueball mass relative to quenched is argued to be (in part at least) a discretisation effect. We find a chiral suppression of the topological susceptibility consistent with expectations, and agreement between fermionic and gluonic methods for measuring the topological charge.Comment: 4pp LaTeX, 4 EPS figures. Contribution to Lattice2001(confinement

The Euclidean two-point correlation function of the topological charge density

We study the Euclidean two-point correlation function $G_q(x)$ of the topological charge density in QCD. A general statement based on reflection positivity tells us that $G_q(x)<0$ for $x\neq 0$. On the other hand the topological susceptibility $\chi_q=\int d^d x G_q(x)$ is a positive quantity. This indicates that $G_q(x)$ developes a positive contact term at $x=0$, that contributes to the determination of the physical value of $\chi_q$. We show explicitly these features of $G_q(x)$ in a solvable nontrivial continuum model, the two-dimensional $CP^{N-1}$ model in the large-N limit. A similar analysis is done on the lattice.Comment: 15 pages, 1 fig. Accepted for publication in Nucl. Phys.

On the Low-Energy Effective Action of N=2 Supersymmetric Yang-Mills Theory

We investigate the perturbative part of Seiberg's low-energy effective action of N=2 supersymmetric Yang-Mills theory in Wess-Zumino gauge in the conventional effective field theory technique. Using the method of constant field approximation and restricting the effective action with at most two derivatives and not more than four-fermion couplings, we show some features of the low-energy effective action given by Seiberg based on $U(1)_R$ anomaly and non-perturbative $\beta$-function arguments.Comment: 27 pages, RevTex, no figure

The connection between mass, environment and slow rotation in simulated galaxies

Recent observations from integral field spectroscopy (IFS) indicate that the fraction of galaxies that are slow rotators, $F_{\rm SR}$, depends primarily on stellar mass, with no significant dependence on environment. We investigate these trends and the formation paths of slow rotators (SRs) using the EAGLE and Hydrangea hydro-dynamical simulations. EAGLE consists of several cosmological boxes of volumes up to $(100\,\rm Mpc)^3$, while Hydrangea consists of $24$ cosmological simulations of galaxy clusters and their environment. Together they provide a statistically significant sample in the stellar mass range $10^{9.5}\,\rm M_{\odot}-10^{12.3}\,\rm M_{\odot}$, of $16,358$ galaxies. We construct IFS-like cubes and measure stellar spin parameters, $\lambda_{\rm R}$, and ellipticities, allowing us to classify galaxies into slow/fast rotators as in observations. The simulations display a primary dependence of $F_{\rm SR}$ on stellar mass, with a weak dependence on environment. At fixed stellar mass, satellite galaxies are more likely to be SRs than centrals. $F_{\rm SR}$ shows a dependence on halo mass at fixed stellar mass for central galaxies, while no such trend is seen for satellites. We find that $\approx 70$% of SRs at $z=0$ have experienced at least one merger with mass ratio $\ge 0.1$, with dry mergers being at least twice more common than wet mergers. Individual dry mergers tend to decrease $\lambda_{\rm R}$, while wet mergers mostly increase it. However, $30$% of SRs at $z=0$ have not experienced mergers, and those inhabit halos with median spins twice smaller than the halos hosting the rest of the SRs. Thus, although the formation paths of SRs can be varied, dry mergers and/or halos with small spins dominate.Comment: Accepted for publications in MNRAS (20 pages, 17 main body, 1.5 appendix). Changes include analysis of the orbital angular momentum effect on lambdaR and slightly different ellipticity calculatio

Perturbative superstrata

Issued under a Creative Commons Attribution LicenceS.G. has been partially supported by MIUR-PRIN contract 2009-KHZKRX, by the Padova University Project CPDA119349 and by INFN. R.R. has been partially supported by STFC Standard GrantST/J000469/1 “String Theory, Gauge Theory and Duality”

Development of a Java-Based Framework for Aircraft Preliminary Design and Optimization

The paper deals with the description of a software tool to be used for aircraft preliminary design and optimization. The software tool, called ADOpT (Aircraft Design and Optimization Tool) has been developed in order to have a fast, reliable and user friendly framework to be used in preliminary/conceptual design phase. The software platform is made to perform fast multi-disciplinary analysis of an established aircraft configuration and search for an optimized configuration in a domain whose boundaries are defined by the user. The software has been conceived to be used in an industrial environment across conceptual and preliminary design phases. The software is still in development at the Department of Industrial Engineering of University of Naples

CFD sensitivity analysis on bumped airfoil characteristics for inflatable winglet

The new aerospace technological milestone is aimed to reducing direct operating costs and pol- lution. In order to obtain pollution reductions via high aerodynamic efficiency, a performance anal- ysis for bumped airfoil based winglet has been pro- posed. Most conventional aircrafts are equipped with fixed winglets to decrease the induced drag; thus, saving more fuel. New projects point to- wards advanced smart materials and telescopic wing tip devices to obtain an adaptive morphing shape that gives, through performance improve- ment, a fuel consumption reduction resulting in less pollutants. The focus of this paper is to evalu- ate the aerodynamic performance, in terms of lift, drag and moment coefficient for a bumped airfoil in climb/descent flight condition at 5000 meters altitude. The performance analysis has been con- ducted via a numerical investigation of the effects of bumps number, height and width for inflatable winglet airfoil, a system that would guarantee a more comfortable arrangement of extraction sys- tem and just minor surplus of weight compared to classical winglet solutions, with all the subsequent advantages

On the large-NcN_c behavior of the L7L_7 coupling in χ\chiPT

It is shown that the usual large-$N_c$ counting of the coupling constant $L_{7}$ of the ${\cal O}(p^4)$ low-energy chiral $SU(3)$ Lagrangian \cite{GL85} is in conflict with general properties of QCD in the large-$N_c$ limit. The solution of this conflict within the framework of a chiral $U(3)$ Lagrangian is explained.Comment: 6 pages, latex(includes macro at the beginning of file), no figure