A common goal of unsupervised learning is to discover the latent variables responsible for generating the observed properties of a set of objects. For example, factor analysis attempts to find a set of latent variables (or factors) that explain the correlations among the observed variables. A problem with factor analysis, however, is that the user has to specify the number of latent variables w...

When modeled within the unsteady Reynolds-averaged Navier–Stokes framework, shock wave dynamics on a two-dimensional airfoil at transonic buffet conditions is characterized by time-periodic oscillations. Given time series of lift coefficient different angles attack for OAT15A supercritical profile, Sparse Identification Nonlinear Dynamics (SINDy) technique used to extract parameterized, interpr...

Abstract This experimental study investigates the possibility of controlling transonic buffet by means a trailing edge flap with an upward deflection (referred to as “upper flap”, or: UTEF). Different geometries (straight and serrated) dimensions UTEFs (with heights ranging between 1 2% chord) have been studied respect their impact on behavior. The effectiveness has investigated schlieren parti...

Deep belief networks are a powerful way to model complex probability distributions. However, it is difficult to learn the structure of a belief network, particularly one with hidden units. The Indian buffet process has been used as a nonparametric Bayesian prior on the structure of a directed belief network with a single infinitely wide hidden layer. Here, we introduce the cascading Indian buff...

This paper presents an extension of the cascading Indian buffet process (CIBP) intended to learning arbitrary directed acyclic graph structures as opposed to the CIBP, which is limited to purely layered structures. The extended cascading Indian buffet process (eCIBP) essentially consists in adding an extra sampling step to the CIBP to generate connections between non-consecutive layers. In the ...

Transonic buffet is an unsteady flow phenomenon that limits the safe flight envelope of modern aircraft. Scale-resolving simulations with span-periodic boundary conditions are capable providing new insights into its physics. The present contribution shows co-existence multiple modes unsteadiness over unswept laminar-flow wing section, appearing in following order increasing frequency: (a) a low...

In this work, the application of harmonic balance technique is demonstrated for transonic buffet cases. The method represents an alternative to time-marching simulations that are expensive complex flow Here applied on different test cases with inherently unsteady flows, i.e. two aerofoil configurations undergoing buffet. A gradient-based, variable time period used estimate frequency oscillation...