Optimal flow control for Navier–Stokes equations: drag minimization

2007 ◽  
Vol 55 (4) ◽  
pp. 347-366 ◽  
Author(s):  
L. Dedè
Keyword(s):  
Flow Control ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Optimal Flow ◽  
Drag Minimization ◽  
Optimal Flow Control

scholarly journals Optimal Flow Sensing for Schooling Swimmers

Biomimetics ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 10
Author(s):  
Pascal Weber ◽  
Georgios Arampatzis ◽  
Guido Novati ◽  
Siddhartha Verma ◽  
Costas Papadimitriou ◽  
...  
Keyword(s):  
Visual Cues ◽  
Stokes Equations ◽  
Center Of Mass ◽  
Quantitative Information ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Optimal Flow ◽  
Flow Sensing ◽  
Fish Schooling

Fish schooling implies an awareness of the swimmers for their companions. In flow mediated environments, in addition to visual cues, pressure and shear sensors on the fish body are critical for providing quantitative information that assists the quantification of proximity to other fish. Here we examine the distribution of sensors on the surface of an artificial swimmer so that it can optimally identify a leading group of swimmers. We employ Bayesian experimental design coupled with numerical simulations of the two-dimensional Navier Stokes equations for multiple self-propelled swimmers. The follower tracks the school using information from its own surface pressure and shear stress. We demonstrate that the optimal sensor distribution of the follower is qualitatively similar to the distribution of neuromasts on fish. Our results show that it is possible to identify accurately the center of mass and the number of the leading swimmers using surface only information.

scholarly journals Development of flow control methods in free and impinging jets

2021 ◽  
Vol 2119 (1) ◽  
pp. 012003
Author(s):  
A K Shevchenko ◽  
S N Yakovenko
Keyword(s):  
Velocity Profile ◽  
Flow Control ◽  
Stokes Equations ◽  
Flow Behavior ◽  
Impinging Jets ◽  
Navier Stokes ◽  
Control Methods ◽  
Navier Stokes Equations ◽  
Inlet Velocity

Abstract Submerged and impinging jets with harmonic perturbations added to the inlet velocity profile and with nozzle vibrations are simulated numerically at different Reynolds (Re) and Strouhal (St) numbers by solving the Navier–Stokes equations. The effects of Re, St and forcing amplitudes on flow behavior and jet splitting phenomena are studied.

Simulation of Microfluidic Flow Using Ferrofluids

2008 ◽  
Author(s):  
Akshay C. Gunde ◽  
Sushanta K. Mitra
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Flow Control ◽  
Magnetic Particles ◽  
Stokes Equations ◽  
Maximum Velocity ◽  
Additional Term ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Microfluidic Flow

Present day microfluidics widely uses electrokinetic effects like eletrosmosis and electrophoresis to achieve flow control. These methods require extensive micromachining processes. Also, the fabrication of valves and valve-seats is difficult, which frequently leads to leakages and eventual breakdown of the system. This paper introduces the use of ferrofluids as an alternative for flow control in microchannels. Numerical simulation of flow through a microchannel using a ferrofluid in the presence of an external magnetic field is performed by coupling the flow and magnetic phenomena. An additional term calculated from the ferrofluid magnetization equations, is introduced in the Navier-Stokes equations to account for the magnetic force. The maximum velocity in a magnetically driven flow is shown to be a linear function of magnitude of magnetization of the permanent magnet. Further, the insertion of micron-size magnetic particles (referred here as magnetic plugs) in the flow field has been discussed. These plugs can be used to provide appropriate barriers to the flow by controlling their movement externally. Using the combination of ferrofluid and magnetic plugs, flow control can be achieved by the variation of external magnetic field alone.

PANS Study of the Flow Around an Oscillating, Simplified Truck Cabin With Flow Control

2017 ◽  
Author(s):  
G. Minelli ◽  
S. Krajnović ◽  
B. Basara
Keyword(s):  
Flow Control ◽  
Stokes Equations ◽  
Numerical Study ◽  
Active Flow Control ◽  
Synthetic Jet ◽  
Navier Stokes ◽  
Dynamic Configuration ◽  
Navier Stokes Equations ◽  
Recirculation Bubble ◽  
Yaw Angle

This work presents an application of the Partially-Averaged Navier-Stokes equations for an external vehicle flow. In particular, the flow around a generic truck cabin is simulated. The PANS method is first validated against experiments and resolved LES on two static cases. As a consequence, PANS is used to study the effect of an active flow control (AFC) on a dynamic oscillating configuration. The oscillation of the model represents a more realistic ground vehicle flow, where gusts (of different nature) define the unsteadiness of the incoming flow. In the numerical study, the model is forced to oscillate with a yaw angle 10° > β > −10° and a non-dimensional frequency St = fW/Uinf = 0.1. The effect of the periodic motion of the model is compared with the quasi-steady flow condition. At a later stage, the dynamic configuration is actuated by means of a synthetic jet boundary condition. Overall, the effect of the actuation is beneficial. The actuation of the AFC decreases drag, stabilises the flow and reduces the size of the side recirculation bubble.

Drag Minimization Based on the Navier–Stokes Equations Using a Newton–Krylov Approach

AIAA Journal ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 1555-1577 ◽  
Author(s):  
Lana Osusky ◽  
Howard Buckley ◽  
Thomas Reist ◽  
David W. Zingg
Keyword(s):  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Drag Minimization

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

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