A kind of Urban Streets Pedestrian Level Winds appraisal procedure based on wind tunnel test
Technical field
The present invention relates to a kind of Urban Streets Pedestrian Level Winds appraisal procedures, and in particular to a kind of city based on wind tunnel test
City block Pedestrian Level Winds appraisal procedure, belongs to architectural wind environment field.
Background technique
With the development of Chinese Urbanization, (super) skyscraper is emerged in multitude, and it is complicated to be laid out multiplicity, the bodily form.City
In high-lager building and groups of building can be significant change surrounding wind field so that avenue, building corner and entrance
Equal regions occur apparent wind speed due to " funnelling " and accelerate, and thus deteriorate the wind environment of pedestrian level, pedestrian is caused to produce
Raw discomfort is even caused danger.
With the raising of people's quality of the life and the comfortable theory of health, the quality of Urban Streets Pedestrian Level Winds is increasingly obtained
Pay attention to.It, need to be in block in order to avoid because of uncomfortable caused by unreasonable construction style and layout, even dangerous Pedestrian Level Winds
Its Pedestrian Level Winds quality is correctly predicted and is assessed at the beginning of planning and designing, and to the second-rate region of wind environment into
Row optimization design.
Wind tunnel test is to study the main method of Urban Streets Pedestrian Level Winds, and use earliest, most widely used at present
General wind environment prediction technique.1981, Irwin invented a kind of omnidirection pressure sensor (wind speed probe), which visits
Head is under conditions of stream field interferes less, it can be achieved that the Multipoint synchronous of whole region pedestrian level wind speed measures.A large amount of wind
Environmental test and rating test show that Irwin wind speed probe can get the measurement result of accurate mean wind speed and fluctuating wind speed,
Suitable for practical engineering project research.
The Pedestrian Level Winds appraisal procedure of Urban Streets mainly include wind speed than Evaluation Method, opposite wind comfort level Evaluation Method and
Exceeded threshold probability assessment method etc..1) wind speed is than Evaluation Method with the pedestrian level mean wind speed of Urban Streets measuring point and identical height
The ratio of distant place incoming flow mean wind speed reflect building there are caused wind speed variation degree, this method can only qualitatively be sentenced
The relative mass quality of the wind environment of other Urban Streets different zones, and it is unrelated with the impression of people (due to that cannot reflect that wind speed is exhausted
To size).Since wind speed is than Evaluation Method simple possible, and accurate assessment result can be obtained, thus this method be at present most
For common method, also used by some codes and standards.2) opposite wind comfort level Evaluation Method is with the comfort demand of people
Point is sent out, the frequency of the corresponding wind speed threshold value of different behaviors of people and the uncomfortable wind of permission is given.But this method fails
The influence for considering building location arrives stream wind speed (meteorological data), can not also reflect the stochastic behaviour of wind speed.3) exceeded threshold
Probability assessment method unites to the local meteorological data of Urban Streets using the comfortableness and security demand of people as starting point
Meter analysis, the pedestrian's mean wind speed for calculating measuring point under full wind angle is more than the probability of mean wind speed threshold value;It is super by comparing measuring point
More probability and maximum allowable outcross probability, quantitatively to assess the Pedestrian Level Winds of Urban Streets.Exceeded threshold probability assessment method
The stochastic behaviour that wind speed is considered by the method for probability is presently the most accurate appraisal procedure.But due to the Evaluation Method
It needs to combine local meteorological data, and algorithm is relative complex, leads to its practical application.
Summary of the invention
The present invention is to solve the problems, such as existing wind environment appraisal procedure precision deficiency, and then propose a kind of based on wind tunnel test
Urban Streets Pedestrian Level Winds appraisal procedure.
The technical solution adopted by the present invention to solve the above problem is as follows: the specific steps of appraisal procedure of the present invention are such as
Under:
Step 1: being demarcated to the parameter of improved Irwin wind speed probe;
Step 2: using acrylic board or PVC board to make with certain scaling factor using typical Urban Streets as research object
The shape of the block nearby owned building and structures, and be arranged at a certain distance at the pedestrian level of block improved
Irwin wind speed probe, to obtain the test model of wind environment test;
Step 3: carrying out wind environment test, the pedestrian level hour for obtaining Urban Streets model under different parameters operating condition is flat
Equal wind velocity UiWith gustiness Ui,gust, wherein gustiness Ui,gustIt can be obtained by following formula:
Ui,gust=Ui+g·σu (1)
In formula (1), g indicates peak factor, usually takes 2.5;σuIndicate wind speed root-mean-square value;
Step 4: determining the hourly average wind of Urban Streets pedestrian level under each wind angle using formula (2) and formula (3)
Fast Ui,siteWith gustiness Ui,gust,siteRespectively with the hourly average wind velocity U of 10m height10,siteRatio rMAnd rG:
U in formula (2) and formula (3)rIndicate the incoming flow mean wind speed in wind environment test at reference altitude, ZrefIt indicates
Urban Streets reference altitude, α indicate the ground roughness exponent of exponential law wind profile;
Step 5: being based on wind speed ratio rMAnd rG, by the hourly average wind speed threshold value U in wind environment evaluation criteriathrIt is converted to
Hourly average wind speed threshold value U at the 10m height of Urban Streetsthr,MOr the equivalent hourly average wind speed threshold value U of fitful windthr,GEM:
In formula, UthrIt is the hourly average wind speed threshold value in Lawson evaluation criteria;1.85 indicate gustiness Ui,gust
It is equivalent to the equivalent hourly average wind velocity U of fitful windi,GEMConversion coefficient, it may be assumed that
Ui,gust=1.85UGEM(6);
Step 6: counting and analyzing the local meteorological data of quasi- assessment Urban Streets, good state wind under 16 wind angles is determined
Wind direction frequency and wind speed probability distribution;Usual meteorological data includes hourly average wind speed and the average wind at 10m height
To;Each measuring point wind velocity U is more than wind speed threshold value U under θ wind anglethr,MOr Uthr,GEMProbability are as follows:
In formula (7) and formula (8), θ=1,2,3 ..., 16, indicate common 16 wind angles number in meteorology,
Wind direction angular spacing is 22.5 °;AθIndicate the wind direction frequency of wind angle θ;cθAnd kθWeibull is distributed letter when respectively indicating wind angle θ
Several scale parameters and form parameter;
Step 7: each measuring point wind velocity U is more than wind speed threshold value U under all wind angles that add upthr,MOr Uthr,GEMProbability, i.e., should
The outcross probability of threshold value wind speed:
Step 8: based on outcross probability P (U > U under full wind anglethr,M) or P (U > Uthr,GEM), and commented in conjunction with Lawson
Estimate the maximum allowable outcross probability P in standardmax, assess comfort and the safety of Urban Streets Pedestrian Level Winds.
The beneficial effects of the present invention are: the 1, present invention is by combining the aerodynamic information of Urban Streets pedestrian level, working as ground vapour
It is comprehensive, consider different parameters work in detail as data and three aspect such as the wind environment evaluation criteria with certain fraction
Urban Streets type, different regions difference and the influence of different pedestrian activities of condition are, it can be achieved that Urban Streets Pedestrian Level Winds
Accurate quantitative analysis assessment;2, wind environment appraisal procedure of the invention can mention for layout designs and the wind environment design of Urban Streets
For foundation, avoids generating discomfort when walk or cause danger.
Detailed description of the invention
Fig. 1 is the Urban Streets Pedestrian Level Winds estimation flow figure based on wind tunnel test, and Fig. 2 is that Irwin wind speed probe is whole
Body structural schematic diagram, Fig. 3 are Irwin wind speed probe rating test figures, and Fig. 4 is Irwin wind speed probe calibration curve schematic diagram, figure
5 be Dalian Area whole year wind rose.
Specific embodiment
Specific embodiment 1: illustrating that present embodiment, one kind described in present embodiment are based on wind-tunnel in conjunction with Fig. 1 to Fig. 4
Specific step is as follows for the Urban Streets Pedestrian Level Winds appraisal procedure of test:
Step 1: being demarcated to the parameter of improved Irwin wind speed probe;
Step 2: using acrylic board or PVC board to make with certain scaling factor using typical Urban Streets as research object
The shape of the block nearby owned building and structures, and be arranged at a certain distance at the pedestrian level of block improved
Irwin wind speed probe, to obtain the test model of wind environment test;
Step 3: carrying out wind environment test, the pedestrian level hour for obtaining Urban Streets model under different parameters operating condition is flat
Equal wind velocity UiWith gustiness Ui,gust, wherein gustiness Ui,gustIt can be obtained by following formula:
Ui,gust=Ui+g·σu (1)
In formula (1), g indicates peak factor, usually takes 2.5;σuIndicate wind speed root-mean-square value;
Step 4: determining the hourly average wind of Urban Streets pedestrian level under each wind angle using formula (2) and formula (3)
Fast Ui,siteWith gustiness Ui,gust,siteRespectively with the hourly average wind velocity U of 10m height10,siteRatio rMAnd rG:
U in formula (2) and formula (3)rIndicate the incoming flow mean wind speed in wind environment test at reference altitude, ZrefIt indicates
Urban Streets reference altitude, α indicate the ground roughness exponent of exponential law wind profile;
Step 5: being based on wind speed ratio rMAnd rG, by the hourly average wind speed threshold value U in wind environment evaluation criteriathrIt is converted to
Hourly average wind speed threshold value U at the 10m height of Urban StreetsthrMOr the equivalent hourly average wind speed threshold value U of fitful windthrGEM:
In formula, UthrIt is the hourly average wind speed threshold value in Lawson evaluation criteria;1.85 indicate gustiness Ui,gust
It is equivalent to the equivalent hourly average wind velocity U of fitful windi,GEMConversion coefficient, it may be assumed that
Ui,gust=1.85UGEM(6);
Step 6: counting and analyzing the local meteorological data of quasi- assessment Urban Streets, good state wind under 16 wind angles is determined
Wind direction frequency and wind speed probability distribution;Usual meteorological data includes hourly average wind speed and the average wind at 10m height
To;Each measuring point wind velocity U is more than wind speed threshold value U under θ wind anglethr,MOr Uthr,GEMProbability are as follows:
In formula (7) and formula (8), θ=1,2,3 ..., 16, indicate common 16 wind angles number in meteorology,
Wind direction angular spacing is 22.5 °;AθIndicate the wind direction frequency of wind angle θ;cθAnd kθWeibull is distributed letter when respectively indicating wind angle θ
Several scale parameters and form parameter;
Step 7: each measuring point wind velocity U is more than wind speed threshold value U under all wind angles that add upthr,MOr Uthr,GEMProbability, i.e., should
The outcross probability of threshold value wind speed:
Step 8: based on outcross probability P (U > U under full wind anglethr,M) or P (U > Uthr,GEM), and commented in conjunction with Lawson
Estimate the maximum allowable outcross probability P in standardmax, assess comfort and the safety of Urban Streets Pedestrian Level Winds.
Improved Irwin wind speed probe is the cylinder of 10mm, a height of 15mm by an outer diameter in present embodiment, and is therefrom dug
The small column of a diameter 6mm, depth 10mm is gone to obtain, pressure port K1 is surveyed by the hollow steel pipe of a 10mm long, 1mm outer diameter
The pressure p 1 on ground is measured, pressure port K2 measures pedestrian level H=6.7mm by the hollow steel pipe of a 26.7mm long, 1mm outer diameter
Pressure at (it is assumed that the length scaling factor of wind environment test is 1/300, then 6.7mm corresponds to actual pedestrian level 2m)
p2。
For improved Irwin wind speed probe, the relationship of pressure p 1, p2 and pedestrian level wind velocity U be may be expressed as:
In formula (13), a and b are respectively wind speed probe parameter, can pass through the measurement result of Pitot tube or hot-wire anemometer
It is demarcated.
Using the mean wind speed U of Pitot tube measurement pedestrian level, and using least square method fitting wind velocity U and pressure differenceBetween linear relationship, as shown in Fig. 4.Table 2 is the fitting result of a and b.
2 probe parameter calibration result of table
It is a kind of based on wind tunnel test described in present embodiment specific embodiment 2: embodiment is described with reference to Fig. 1
Improved Irwin wind speed probe is 10mm, a height of by an outer diameter in the step of Urban Streets Pedestrian Level Winds appraisal procedure one
The cylinder of 15mm, and therefrom cut out a diameter 6mm, the small column of depth 10mm obtains.The pressure p 1 on measurement ground can be passed through
With the pressure p 2 at pedestrian level H=6.7mm, to calculate pedestrian level wind velocity U.Other compositions and connection relationship and specific implementation
Mode one is identical.
It is a kind of based on wind tunnel test described in present embodiment specific embodiment 3: embodiment is described with reference to Fig. 1
The spacing of improved Irwin wind speed probe is not less than 40mm in the step of Urban Streets Pedestrian Level Winds appraisal procedure two, to subtract
Small wind speed probe stream field interferes with each other;And the test wind should be remained above 10m/s, to guarantee the test essence of wind speed probe
Degree;Acrylic board or PVC board production can be used in model in wind tunnel.Other compositions and connection relationship and one phase of specific embodiment
Together.
It is a kind of based on wind tunnel test described in present embodiment specific embodiment 4: embodiment is described with reference to Fig. 1
The step of Urban Streets Pedestrian Level Winds appraisal procedure three, Step 4: in step 5 Urban Streets pedestrian level hourly average
Wind velocity Ui, hourly average wind speed ratio rMWith hourly average wind speed threshold value Uthr,MHourly average wind speed gas corresponding to Urban Streets
Dynamic information;The gustiness U of Urban Streets pedestrian leveli,gust, gustiness ratio rGWith the equivalent hourly average wind speed threshold of fitful wind
Value Uthr,GEMThe equivalent hourly average wind speed aerodynamic information of fitful wind corresponding to Urban Streets;The two is used equally for Urban Streets pedestrian
The assessment of wind environment.Other compositions and connection relationship are same as the specific embodiment one.
It is a kind of based on wind tunnel test described in present embodiment specific embodiment 5: embodiment is described with reference to Fig. 1
In the step of Urban Streets Pedestrian Level Winds appraisal procedure six and step 7 under each wind angle Weibull distribution function parameter,
Including wind direction frequency Aθ, scale parameter cθWith form parameter kθ, it is that local meteorological data where Urban Streets statisticallys analyze
It arrives.Other compositions and connection relationship are same as the specific embodiment one.
It is a kind of based on wind tunnel test described in present embodiment specific embodiment 6: embodiment is described with reference to Fig. 1
Hour mean wind speed threshold value U in the step of Urban Streets Pedestrian Level Winds appraisal procedure five and step 8thrSurmount with maximum allowable
Probability PmaxIt is provided by Lawson evaluation criteria.The wind environment evaluation criteria assesses wind environment according to the different feeling of pedestrian
It is divided into Evaluation of Comfort and risk assessment, while is finely divided again according to the difference activity of pedestrian and different assessment places, it is right
It should be in different hourly average wind speed threshold value UthrWith maximum allowable outcross probability Pmax.By comparing the outcross probability P of each measuring point
(U>Uthr,M) or P (U > Uthr,GEM) and maximum allowable outcross probability Pmax, it is horizontal to comfort and risk level accurate to realize
It is quantitatively evaluated.Other compositions and connection relationship are same as the specific embodiment one.
Embodiment:
By taking Dalian Area as an example, the statistical analysis technique of meteorological data is described in detail.Meteorological data generally includes at 10m height
Hourly average wind speed and mean wind direction.The statistical analysis of meteorological data wind speed and direction data is to obtain the general of good state wind wind speed
Rate distribution function is more than Urban Streets wind speed threshold value U for calculating each measuring point wind velocity Uthr,MOr Uthr,GEMProbability, to assess
The quality of Urban Streets Pedestrian Level Winds.
The two-parameter distribution of Weibull is a kind of probability Distribution Model of universally recognized good state wind Maximum wind speed, the present invention
The parameter of Weibull probability-distribution function is fitted by the meteorological data of Dalian Area.According in Daliang City's Meteorological Services
By hourly average wind speed and direction observational data at 2004~2014 10m height in Dalian Area that the heart provides, amount to effective sample
Sheet 95981, statistical analysis and conversion obtain hourly average wind speed, wind direction frequency and the Weibull distribution of 16 wind angles
Parameter value, as shown in table 3.Attached drawing 5 gives the annual wind rose of Dalian Area.
Hourly average wind speed and Weibull distribution parameter of the table 3 based on meteorological data
Wind direction frequency A in formula (7) and formula (8) under each wind angle can be obtained by table 3θ, scale parameter cθAnd form parameter
kθ.Convolution (9) and formula (10) and Urban Streets wind speed threshold value Uthr,MOr Uthr,GEM, can be calculated super under full wind angle
More probability P (U > Uthr,M) or P (U > Uthr,GEM);Later, by comparing outcross probability P (U > Uthr,M) or P (U > Uthr,GEM) and most
Outcross probability P is allowed greatlymax, to assess comfort and the safety of Urban Streets Pedestrian Level Winds.
The above described is only a preferred embodiment of the present invention, be not intended to limit the present invention in any form, though
So the present invention has been disclosed as a preferred embodiment, and however, it is not intended to limit the invention, any technology people for being familiar with this profession
Member, without departing from the scope of the present invention, when the technology contents using the disclosure above are modified or are modified
For the equivalent embodiment of equivalent variations, but without departing from the technical solutions of the present invention, according to the technical essence of the invention,
Within the spirit and principles in the present invention, any simple modifications, equivalent substitutions and improvements to the above embodiments etc., still
Belong within the protection scope of technical solution of the present invention.