System and method for optimizing passive control strategies of oscillatory instabilities in turbulent systems using finite-time Lyapunov exponents

Patent metadata

Field	Value
Publication number	US-11378488-B2
Application number	US-202016894052-A
Country	US
Kind code	B2
Filing date	Jun 5, 2020
Priority date	Jun 6, 2019
Publication date	Jul 5, 2022
Grant date	Jul 5, 2022

Abstract

A system and method for optimizing passive control strategies of oscillatory instabilities in turbulent systems using finite-time Lyapunov exponents are disclosed. The method includes receiving data from one or more measuring devices connected to the turbulent flow system incorporating a control strategy in the flow field. One or more flow characteristics are determined from the data obtained from the measuring devices. The method involves computing critical dynamics from backward time finite-time Lyapunov exponent (FTLE) field based on the one or more flow characteristics. Next, one or more regions of critical dynamics associated with impending oscillatory instabilities in the turbulent flow system are identified. The identified region of critical dynamics is disrupted the control the onset of oscillatory instabilities in the turbulent flow system.

First claim

What is claimed is:

1. A computer implemented method of controlling onset of oscillatory instabilities in a turbulent flow system, the method comprising:
receiving data from one or more measuring devices connected to the turbulent flow system incorporating a control strategy in the flow field;
determining one or more flow characteristics from the data obtained from the measuring devices;
computing critical dynamics from backward time finite-time Lyapunov exponent (FTLE) fields based on the one or more flow characteristics;
identifying one or more regions of critical dynamics associated with impending oscillatory instabilities in the turbulent flow system; and
disrupting the identified region of critical dynamics to control the onset of oscillatory instabilities in the turbulent flow system.

2. The method as claimed in claim 1 , wherein the data is received using Particle Image Velocimetry (PIV) technique or Computational Fluid Dynamics (CFD) methods comprising Direct Numerical Simulations (DNS) and Large Eddy Simulation (LES), and a photomultiplier tube and high speed cameras.

3. The method as claimed in claim 1 , comprising performing signal conditioning processes on the data obtained from measuring device, wherein the signal conditioning processes comprises noise filtering and signal amplification.

4. The method as claimed in claim 1 , wherein the flow characteristics comprises computation of a flow-map function indicative of the displacement of fluid parcels for one or more time intervals.

5. The method as claimed in claim 1 , wherein identifying one or more critical regions comprises selecting one or more regions above a predetermined threshold value in the FTLE fields.

6. The method as claimed in claim 1 , wherein the control strategy comprises an active control strategy in the flow field, the active control strategy comprising actuating a valve to control the flow velocity to control the onset of oscillatory instabilities in the turbulent flow system.

7. A system for controlling onset of oscillatory instabilities in a turbulent flow system, the system comprising:
a memory unit;
one or more measuring devices configured to measure data associated with turbulent flow system incorporating a control strategy in the flow field;
a processor coupled to the memory unit, wherein the processor is configured to:
receive data from one or more measuring devices connected to the turbulent flow system;
determine one or more flow characteristics from the data obtained from the measuring devices;
compute critical dynamics from backward time finite-time Lyapunov exponent (FTLE) fields based on the one or more flow characteristics; and
identify one or more regions of critical dynamics associated with impending oscillatory instabilities in the turbulent flow system; and

a passive control unit configured to disrupt the identified region of critical dynamics to control the onset of oscillatory instabilities in the turbulent flow system.

8. The system as claimed in claim 7 , wherein one or more measuring devices comprise:
a system to perform Particle Image Velocimetry (PIV), photo multiplier tube, and high speed cameras.

9. The system as claimed in claim 7 , comprising: a control unit configured to receive the identified one or more critical regions and control the operation of an actuating device.

10. The system as claimed in claim 9 , wherein the actuating device is configured to actuate a valve to control the flow velocity to control the onset of oscillatory instabilities in the turbulent flow system.

11. A computer program product having non-volatile memory therein, carrying computer executable instructions stored therein to control onset of oscillatory instabilities in a turbulent flow system, the instructions comprising:
receiving data from one or more measuring devices connected to the turbulent flow system incorporating a control strategy in the flow field;
determining one or more flow characteristics from the data obtained from the measuring devices;
computing critical dynamics from backward time finite-time Lyapunov exponent (FTLE) fields based on the one or more flow characteristics;
identifying one or more regions of critical dynamics associated with impending oscillatory instabilities in the turbulent flow system; and
disrupting the identified region of critical dynamics to control the onset of oscillatory instabilities in the turbulent flow system.

Assignees

• Indian Inst Tech Madras

Inventors

• Premakumari Premchand Chandramouly
• Nair Vineeth
• Nair Sujith Raman Pillai Indusekharan
• George Nitin Babu
• Raghunathan Manikandan
• Unni Vishnu Rajasekharan

Classifications

• G01M9/067 Primary

  visualisation · CPC title

• G01P5/001

  Full-field flow measurement, e.g. determining flow velocity and direction in a whole region at the same time, flow visualisation · CPC title

• G01P5/00

  Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft (application of speed-measuring devices for measuring volume of fluid G01F) · CPC title