U. S. Department of Housing and Urban Development



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U.S. Department of Housing and Urban Development

Office of Policy Development and Research


Monitoring of Near Ground Wind

in a Built-up Suburban Environment


Monitoring of Near Ground Wind

in a Built-up Suburban Environment

Prepared for:
The U.S. Department of Housing and Urban Development

Office of Policy Development and Research

Washington, DC
and
The National Association of Home Builders

Housing Affordability Through Design

Efficiency Program

Washington DC


Prepared by:


NAHB Research Center, Inc.

Upper Marlboro, MD


Contract H-21065CA


September 1998




Notice
The U.S. Government does not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the object of this report.

The contents of this report are the views of the contractor and do not necessarily reflect the views or policies of the Department of Housing and Urban Development or the U.S. Government.


Acknowledgments

The NAHB Research Center, Inc., expresses great appreciation to the U.S. Department of Housing and Urban Development and the National Association of Home Builders for their sponsorship and continued interest in more affordable design and construction practices for residential buildings. William Freeborne of the U.S. Department of Housing and Urban Development, Office of Policy Development and Research, is recognized for his contributions to and continued interest in this work.


The Research Center personnel involved in this work include:
Jay Crandell, P.E

William Farkas, P.E.

James Lyons

Lynda Marchman





TABLE OF CONTENTS


Acknowledgments iii

Executive Summary xi

Introduction 1

Problem Statement 2

Literature Review 3

Historical Basis (Wind Profile) 4

Historical Basis of Wind Engineering 4

Canopy Flow (Wind in the Interfacial Layer) 9

Modern Wind Engineering 12

Summary of Key Findings in the Literature 18

Review of ASCE 7-95 19

Wind Monitoring Approach 23

Results 28

Selected Wind Events 28

Power Law Wind Profile 29

Turbulence Intensity Profile 39

Conclusions 41

Recommendations 42

References 43


Appendix - Ground Station Terrain Descriptions

LIST OF TABLES


TABLE 1 6

POWER LAW EXPONENTS 6

FOR VARIOUS DESCRIPTIONS OF TERRAIN 6

BY DAVENPORT (1960) [3] 6

TABLE 2 7

VARIATION IN GUSTINESS WITH HEIGHT 7

IN A TERRAIN CHARACTERIZED BY A POWER LAW 7

EXPONENT OF 1/4.75 7

TABLE 3 10

SELECT LEAST-SQUARES SOLUTIONS FOR THE 10

ATTENUATION COEFFICIENT [5] 10

TABLE 4 16

ESTIMATES OF DISPLACEMENT HEIGHT (D) 16

AND AERODYNAMIC ROUGHNESS (ZO) 16

FOR VARIOUS SHAPES [12] 16

TABLE 5 22

HISTORY OF THE POWER LAW EXPONENT, a, 22

IN THE ASCE 7 STANDARD [1],[14] 22

TABLE 6 29

SUMMARY DATA FOR ALL WIND EVENTS DURING THE PERIOD OF RECORD 29

Table A-1 - Characteristics of Monitoring Locations 1


LIST OF FIGURES




Figure 1 3

Interfacial Layer 3

Figure 2 - Portable near-ground wind station 23

with a anemometer at a 10-ft (3-m) height above ground. 23

Figure 3a - Lower tower anemometer 24

at a 33-ft (10-m) height above ground. 24

Figure 3b - Upper tower anemometer 24

at a 187-ft (57 m) height above ground. 24

Figure 4 - Aerial photograph of 10-ft (3-m) height wind monitoring stations 26

with an approximate scale of 1:8400. The tower station with anemometers at 33-ft (10-m) and 187-ft (57 m) heights is labeled as #2. 26

Figure 5 - Maximum hourly gust trace for ground stations 28

Figure 6 - Plot of estimated  for daily peak gust wind measurements based on 187-ft (57-m) tower anemometer and 33-ft (10-m) tower anemometer. 30

Figure 7 - Plot of estimated  for daily maximum 1-minute mean wind measurements based on 187-ft (57-m) tower anemometer and 33-ft (10-m) tower anemometer. 30

Figure 8 - Plot of estimated  for daily maximum 10-minute mean wind measurements based on 187-ft (57-m) tower anemometer and 33-ft (10-m) tower anemometer. 31

Figure 9 - Plot of estimated  for daily peak gust wind measurements based on 187-ft (57-m) tower anemometer and 10-ft (3-m) tower anemometer. 31

Figure 10 - Plot of estimated  for daily maximum 1-minute mean wind measurements based on 187-ft (57-m) tower anemometer and 10-ft (3-m) tower anemometer. 32

Figure 11 - Plot of estimated  for daily maximum 10-minute mean wind measurements based on 187-ft (57-m) tower anemometer and 10-ft (3-m) tower anemometer. 32

Figure 12 - Plot of COV of  for daily peak gust wind measurements based on the 187-ft (57-m) tower anemometer and the 10-ft (3-m) near-ground anemometers. 33

Figure 13 - Plot of COV of  for daily maximum 1-minute mean wind measurements based on 187-ft (57-m) tower anemometer and the 10-ft (3-m) near-ground anemometers. 34

Figure 14 - Plot of COV of  for daily maximum 10-minute mean wind measurements based on 187-ft (57-m) tower anemometer and the 10-ft (3-m) near-ground anemometers. 34

Figure 15 - Power law profile for peak gust wind speeds based on the 187-ft (57-m) tower data and an assumed gradient height of 1,200 ft (366 m). 36

Figure 16 - Power law profile for maximum 1-minute mean wind speeds based on the 187-ft (57-m) tower data and an assumed gradient height of 1,200 ft (366 m). 37

Figure 17 - Power law profile for maximum 10-minute mean wind speeds based on the 187-ft (57-m) tower data and an assumed gradient height of 1,200 ft (366 m). 38

Figure 18 - Turbulence intensity profile for a 1-minute period 39

at the time of each station’s peak gust record. 39

Figure 19 - Turbulence intensity profile for a 10-minute 40

period at the time of each station’s peak gust record. 40

Figure A-1 - View Looking Northwest 2

(Station 1) 2

Figure A-3 - View Looking East 2

(Station 1) 2

Figure A-2 - View Looking Northeast 2

(Station 1) 2

Figure A-4 - View Looking Southeast 2

(Station 1) 2

Figure A-5 - View Looking South 3

(Station 1) 3

Figure A-7 – View Looking West 3

(Station 1) 3

Figure A-6 - View Looking Southwest 3

(Station 1) 3

Figure A-8 – View Looking Northwest 3

(Station 1) 3

Figure A-9 - View Looking North 4

(Station 3) 4

FigureA-11 - View Looking East 4

(Station 3) 4

Figure A-10 - View Looking Northeast 4

(Station 3) 4

Figure A-12 - View Looking Southeast 4

(Station 3) 4

Figure A-13 - View Looking South 5

(Station 3) 5

FigureA-15 - View Looking West 5

(Station 3) 5

Figure A-14 - View Looking Southwest 5

(Station 3) 5

Figure A-16 - View Looking Northwest 5

(Station 3) 5

Figure A-17 - View Looking North 6

(Station 4) 6

Figure A-19 - View Looking East 6

(Station 4) 6

Figure A-18 - View Looking Northeast 6

(Station 4) 6

Figure A-20 - View Looking Southeast 6

(Station 4) 6

Figure A-21 - View Looking South 7

(Station 4) 7

Figure A-23 - View Looking West 7

(Station 4) 7

Figure A-22 - View Looking Southwest 7

(Station 4) 7

Figure A-24 - View Looking Northwest 7

(Station 4) 7

Figure A-25 - View Looking North 8

(Station 5) 8

Figure A-27 - View Looking East 8

(Station 5) 8

Figure A-26 - View Looking Northeast 8

(Station 5) 8

Figure A-28 - View Looking Southeast 8

(Station 5) 8

Figure A-29 - View Looking South 9

(Station 5) 9

Figure A-31 - View Looking West 9

(Station 5) 9

Figure A-30 - View Looking Southwest 9

(Station 5) 9

Figure A-32 - View Looking Northwest 9

(Station 5) 9

Figure A-33 - View Looking North 10

(Station 6) 10

Figure A-35 - View Looking East 10

(Station 6) 10

Figure A-34 - View Looking Northeast 10

(Station 6) 10

Figure A-36 - View Looking Southeast 10

(Station 6) 10

Figure A-37 - View Looking South 11

(Station 6) 11

Figure A-39 - View Looking West 11

(Station 6) 11

Figure A-38 - View Looking Southwest 11

(Station 6) 11

Figure A-36 - View Looking Northwest 11

(Station 6) 11

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