Two separate experiments were conducted on a three-bladed NACA0012 rotor operating at a blade tip Reynolds number ranging from 44 − 110 × 10 3 using phase-locked infrared thermography (IRT) coupled with force and torque measurements. The first experiment consisted of a parametric study on the impact of forcing boundary layer transition using roughn...
This paper is devoted to the study of numerical methods used in the analysis of a thermal transient flight cycle. Two priorities are stressed. The first one concerns a stability issue, namely the fluid-solid interface conditions. The main properties of the Dirichlet-Robin and Neumann-Robin conditions are first recalled, before proposing for the fir...
Experiments were conducted to study the transition and flow development in a laminar separation bubble (LSB) formed on an aerofoil. The effects of a wide range of freestream turbulence intensity (0.15%
In a linear input-output analysis framework, the most amplified instabilities are typically described by considering singular vectors of the resolvent operator of the linearized Navier-Stokes equations. In this study, we extend the methodology to take into account nonlinear triadic interactions by considering a finite number of harmonics in the fre...
We identify the nonlinear optimal mechanisms at the edge of the turbulent regime through solution of the frequency-domain Harmonic-Balanced Navier-Stokes equations. Specifically, we seek the optimal harmonic or multi-harmonic forcing mechanisms that maximise the skin friction coefficient asymptotically in time, which can be viewed as the minimal fo...
The Kitanidis filter is a natural extension of the Kalman filter to systems subject to arbitrary disturbances or unknown inputs. Though the optimality of the Kitanidis filter was founded for general time varying systems more than 30 years ago, its stability analysis is still limited to time invariant systems, to the author's knowledge. In the frame...
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Crack nucleation has been the subject of important contributions in the two last decades. However, it seems that few attention has been granted to the case of saturated porous media. This is the question adressed in the present paper which is devoted to nucleation in traction mode. From a physical point of view, nucleation is a sudden phenomenon, s...
The present article aims at optimising the spread of a bifurcating jet: a jet that combines axisymmetric and helical forcing to achieve increased mixing in a preferential plane. Parekh et al. (Tech. Rep. TF-35, Stanford University, 1988) explained such a bifurcation as the result of nonlinear interaction between ring vortices (triggered by m D 0 ax...
