OLS : Record

RECORD NUMBER: 42 OF 44

Main Title

An experimental study of turbulence in an urban environment /

Author

Clarke, John F.

Publisher

U.S. Environmental Protection Agency, Environmental Sciences Research Laboratory,

Place Published

Research Triangle Park, N.C.

Year Published

1982

Report Number

EPA-600/S3-82-062

OCLC Number

10290794

Subject Added Ent

Turbulence.; Turbulent boundary layer.

Internet Access

Description	Access URL
	http://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=2000TSL1.txt

Holdings

Library		Call Number	Additional Info	Location	Date Modified
EJBD		EPA 600-S3-82-062	c.1	Headquarters Library/Washington,DC	08/10/2011
EJBD	ARCHIVE	EPA 600-S3-82-062		Headquarters Library/Washington,DC	10/13/2009

Collation

5 p. : ill. ; 28 cm.

Notes

Caption title. "August 1982." At head of title: Project summary. Distributed to depository libraries in microfiche. "EPA-600/S3-82-062."

Contents Notes

The structure of turbulence in the urban surface boundary layer is discussed. Wind and temperature fluctuations were measured with fast-response sensors at a height of 31 m in four land-use areas in the St. Louis environs (a rural and three urban sites). The second moments of the fluctuations were computed for one-hour time series and analyzed within the framework of the Monin-Obukhov similarity theory (i.e., normalized by appropriate velocity and temperature scales). The results are discussed relative to observed land-use features and calculated surface roughness lengths for each of the sites. Average surface roughness lengths ranged from 0.7 to 1.7 m for the urban sites, varying by several meters as a function of wind direction at individual sites. The normalized velocity and temperature variances for the rural site were consistent with the Monin-Obukhov similarity theory. For the urban sites, plots of the normalized velocity variances showed an orderly departure from similarity theory for both neutral and unstable stratifications; they were smaller than the corresponding normalized variance for the rural site. The urban anomalies to similarity theory are discussed relative to the terms in the turbulent kinetic energy budget equation. For neutral stratification, the anomaly is suggested to be due to the wake region of the roughness elements extending to near the height of the measurements. For unstable stratification, it is suggested to be due to increased importance of vertical transport processes within the urban area. Ancillary analyses suggest that the spectral peak wavelength may be a more appropriate scaling length for free convection similarity than the height of the mixed layer, z,. During the afternoon transition period the two scales may differ significantly.

Author Added Ent

Ching, J. K. S.;

Godowitch, J. M.

Corporate Au Added Ent

Environmental Sciences Research Laboratory.

PUB Date Free Form

1982

BIB Level

OCLC Time Stamp

20091008115705

Cataloging Source

OCLC/T

Language

eng

SUDOCS Number

EP 1.89/2:T 84

Origin

OCLC

Type

CAT

OCLC Rec Leader

03115cam 2200373Ia 45020

OLS : Record

RECORD NUMBER: 42 OF 44

Local Navigation