Experimental investigation of turbulent coherent structures interacting with a porous airfoil

Abstract: The flow field on solid and porous airfoils subjected to turbulence shed by an upstream cylindrical rod and the corresponding far-field noise radiations are studied through particle image velocimetry (PIV) and microphone measurements, respectively. Three different Reynolds numbers based on the rod diameter are considered in a range...

Plasma Actuation for Mitigation of Fluctuating Loads on Airfoils: An Experimental Study

Wind tunnel measurements are performed to investigate the potential for mitigation of aerodynamic load fluctuations on airfoils, as the main source of fatigue for wind turbines, using plasma actuators. The experiment consists of aerodynamic force measurements using six strain gauges and 2-component velocity measurements using particle image...

POD-Based Deflation Method For Reservoir Simulation

Simulation of flow through highly heterogeneous porous media results in large ill-conditioned systems of equations. In particular, solving the linearized pressure system can be especially time-consuming. Therefore, extensive efforts to find ways to address this issue effectively are required. In this work, we introduce a POD-based deflation...

Kubernetes cluster optimization using hybrid shared-state scheduling framework

This paper presents a novel approach for scheduling the workloads in a Kubernetes cluster, which are sometimes unequally distributed across the environment or deal with fluctuations in terms of resources utilization. Our proposal looks at a hybrid shared-state scheduling framework model that delegates most of the tasks to the distributed...

On POD-based Deflation Vectors for DPCG applied to porous media problems

We study fast and robust iterative solvers for large systems of linear equations resulting from simulation of flow trough strongly heterogeneous porous media. We propose the use of preconditioning and deflation techniques, based on information obtained frfrom the system, to reduce the time spent in the solution of the linear system.An important...

A Semi-Continuous Formulation for Goal-Oriented Reduced-Order Models

A semi-continuous formulation is introduced for finding bases which minimise the error in a specific output functional of a reduced-order model. The formulation is advantageous in that it can be easily applied to nonlinear problems and functionals. A general description of the approach is given, then explicit formulations are derived for the...

Proper orthogonal decomposition of the flow in geometries containing a narrow gap

Geometries containing a narrow gap are characterized by strong quasi-periodical flow oscillations in the narrow gap region. The above mentioned phenomena are of inherently unstable nature and, even if no conclusive theoretical study on the subject has been published, the evidence shown to this point suggests that the oscillations are connected...

Model reduction through multilinear singular value decompositions

This paper considers the problem of optimal rank approximation of multilinear functions. A new notion of singular values is introduced for an arbitrary tensor and it is shown how optimal lower rank approximations of a tensor can be inferred from these singular values, without resorting to orthogonal tensor decompositions. The results in this...

Numerical investigation of the aerodynamic noise from a forward-facing step

In the present study, aerodynamic noise from a forward-facing step is numerically investigated for Reynolds number based on the step height, Reh=8,000 and flow Mach number, M=0.03. A three-dimensional flow over the forward-facing step is calculated by the incompressible large eddy simulation (LES), while its acoustic field is solved by the...

Multiple impinging jet arrays. An experimental study on flow and heat transfer

Because of their high efficiency and their ability to provide high heat transfer rates, impinging jets are applied for rapid cooling and heating in a wide variety of industrial processes. However, the physical phenomena controlling the heat transfer from impinging jets are to a large degree unknown. The goal of the present project was to gain a...