Anemometry tools and procedures for greenhouse experiments
Funk, Ted L.
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/20024
Description
Title
Anemometry tools and procedures for greenhouse experiments
Author(s)
Funk, Ted L.
Issue Date
1994
Doctoral Committee Chair(s)
Christianson, Leslie L.
Department of Study
Agricultural and Biological Engineering
Discipline
Agricultural Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Agriculture, Plant Culture
Engineering, Agricultural
Language
eng
Abstract
Greenhouses provide a useful environment for conducting plant studies, facilitating manipulation and measurement of many variables in the plant microclimate. Photosynthesis, transpiration, thigmomorphogenic responses, and particle transport all depend on the level of air speed at the leaf/atmosphere interface, the microclimate. Yet there seems to exist no standard method of measuring and documenting air velocity in greenhouses.
This study was undertaken to determine the airflow parameters for describing the greenhouse microclimate; to investigate anemometer systems best adapted to measurements; to measure airflows in typical greenhouses so that appropriate instruments and procedures might be recommended; and to propose and test a set of measurement procedures for the greenhouse research scientist.
Literature review showed a divergence of methodology used in greenhouse versus field crop microclimate studies. Greenhouse research literature predominately used single-leaf models, while atmospheric boundary layer research developed whole-canopy models. An integration of the two approaches is needed so that an entire experimental area in a greenhouse can be characterized with a few key air speed measurements.
The greenhouse measurements pointed out the inappropriateness of certain anemometer systems, particularly those which have a markedly directional response. Three research anemometers and three hand-held commercial grade anemometers were evaluated. Most of the kinetic energy in the turbulence spectra was contained in frequencies of less than 5 Hz. Omnidirectional anemometers were shown to be sufficient and convenient for assessing mean velocities over the plant canopies. However, the highly turbulent conditions within the plant canopy may be better studied with tools other than heated element anemometers.
Each of the greenhouse rooms measured showed a range of microclimate air velocity means of at least seven to one, except for a commercial fan-tube ventilated greenhouse which had a range of only 2.4 to one. The broad range of means emphasized the need for documentation of air speeds during experiments.
Profiles of air speed over the plant canopies showed that the proposed standardized measurement height over the canopy can give meaningful data. A grid system was tested and shown useful in representing rectangular experimental areas of various sizes.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
