System and method for wind flow turbulence measurement by LiDAR in a complex terrain

Patent metadata

Field	Value
Publication number	US-11442076-B2
Application number	US-202016838161-A
Country	US
Kind code	B2
Filing date	Apr 2, 2020
Priority date	Apr 2, 2020
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

A wind flow sensing system for determining a turbulence of wind flow at a set of different altitudes above a terrain is provided. The wind flow sensing system comprises an input interface configured to receive a set of measurements of radial velocities at line-of-site points above the terrain for each of the altitudes for a set of time steps, and a processor configured to estimate velocity fields for each of the altitudes based on data assimilation of the velocity fields, estimate unbiased horizontal velocities at each of the altitudes and for each time step, determine an average of the unbiased horizontal velocities for a period of time including the set of time steps, and determine, at each of the altitudes, a turbulence based on the unbiased horizontal velocities for each time step and the average of the unbiased horizontal velocity.

First claim

The invention claimed is:

1. A wind flow sensing system for determining a turbulence of wind flow at a set of different altitudes above a terrain from a set of measurements of radial velocities at each of the altitudes, comprising:
an input interface configured to receive the set of measurements of radial velocities at line-of-site points above the terrain for each of the altitudes for a set of time steps;
a processor configured to:
estimate velocity fields for each of the altitudes based on data assimilation of the velocity fields above the terrain to fit the measurements of radial velocities, wherein the velocity fields are estimated for the set of time steps;
estimate unbiased horizontal velocities at each of the altitudes and for each time step as a horizontal projection of the corresponding radial velocities corrected with corresponding horizontal derivatives of vertical velocities of the estimated velocity fields determined for the corresponding time step;
determine, at each of the altitudes, an average of the unbiased horizontal velocities for a period of time including the set of time steps; and
determine, at each of the altitudes, a turbulence based on the unbiased horizontal velocities for each time step and the average of the unbiased horizontal velocity; and

an output interface configured to render the turbulence at each of the altitudes.

2. The wind flow sensing system of claim 1 , wherein the data assimilation is performed by simulating computational fluid dynamics (CFD) of the wind flow or by analytical fluid mechanics approximation using potential flow approximation.

3. The wind flow sensing system of claim 2 , wherein the processor is configured to:
determine boundary conditions for an inlet velocity field;
perform the simulation of the CFD by solving Navier-Stokes equations defining the wind flow with the boundary conditions; and
update the boundary conditions and repeat the simulation until a termination condition is met.

4. The wind flow sensing system of claim 2 , wherein the processor is configured to:
approximate a non-convex shape of the terrain using a set of convex shapes;
determine boundary conditions for an inlet velocity field;
derive analytical solution of Laplacian equations defining the wind flow with the boundary conditions; and
update the boundary conditions and repeat the simulation until a termination condition is met.

5. The wind flow sensing system of claim 1 , wherein the turbulence includes an intensity of the turbulence determined according to a ratio of root-mean-square of turbulent velocity fluctuations over the average unbiased horizontal velocity.

6. The wind flow sensing system of claim 1 , wherein the turbulence includes kinetic energy of the turbulence determined according to half of sum of root-mean-square of the turbulent velocity fluctuations.

7. The wind flow sensing system of claim 1 , wherein the period of time is multiple of 10 minutes and difference between time steps is multiple of a second.

8. The wind flow sensing system of claim 1 , further comprising:
a memory configured to store a correction function trained to correct the unbiased horizontal velocities, wherein the processor applies the correction function to correct the unbiased horizontal velocities before estimating the turbulence.

9. The wind flow sensing system of claim 8 , wherein the correction function is trained to reduce a difference between ground truth and the unbiased horizontal velocities determined based on simulating computational fluid dynamics (CFD) of the wind flow by solving Navier-Stokes equations.

10. The wind flow sensing system of claim 8 , wherein the correction function is trained to reduce a difference between ground truth and the unbiased horizontal velocities determined based on analytical solution of Laplacian equations defining the wind flow over an approximated terrain.

11. The wind flow sensing system of claim 1 , further comprising a controller of a wind turbine to control the wind turbine based on one or more of the estimated unbiased horizontal velocities at each of the altitudes, or the turbulence at each of the altitudes, wherein the wind turbine is operatively connected to the wind flow sensing system of claim 1 .

12. A wind flow sensing method for determining a turbulence of wind flow at a set of different altitudes above a terrain from a set of measurements of radial velocities at each of the altitudes, wherein the method uses a processor coupled with stored instructions implementing the method, wherein the instructions, when executed by the processor carry out steps of the method, comprising:
receiving the set of measurements of radial velocities at line-of-site points above the terrain for each of the altitudes for a set of time steps;
estimating velocity fields for each of the altitudes based on data assimilation of the velocity fields above the terrain to fit the measurements of radial velocities, wherein the velocity fields are estimated for the set of time steps;
estimating unbiased horizontal velocities at each of the altitudes and for each time step as a horizontal projection of the corresponding radial velocities corrected with corresponding horizontal derivatives of vertical velocities of the estimated velocity fields determined for the corresponding time step;
determining, at each of the altitudes, an average of the unbiased horizontal velocities for a period of time including the set of time steps; and
determining, at each of the altitudes, a turbulence based on the unbiased horizontal velocities for each time step and the average of the unbiased horizontal velocity; and
outputting the turbulence at each of the altitudes.

13. The wind flow sensing method of claim 12 , wherein the data assimilation is performed by simulating computational fluid dynamics (CFD) of the wind flow or by analytical fluid mechanics approximation using potential flow approximation.

14. The wind flow sensing method of claim 12 , wherein the turbulence includes an intensity of the turbulence determined according to a ratio of root-mean-square of turbulent velocity fluctuations over the average unbiased horizontal velocity.

15. The wind flow sensing method of claim 12 , wherein the turbulence includes kinetic energy of the turbulence determined according to half of sum of root-mean-square of the turbulent velocity fluctuations.

Assignees

• Mitsubishi Electric Res Laboratories Inc

Inventors

• Nabi Saleh

Classifications

• F05B2260/84

  Modelling or simulation · CPC title

• G01S17/58

  Velocity or trajectory determination systems; Sense-of-movement determination systems · CPC title

• F05B2270/32

  Wind speeds · CPC title

• G01S15/885

  Meteorological systems · CPC title

• G01S17/95

  for meteorological use · CPC title