• Title, Summary, Keyword: full-scale measurements

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Comparison between wind load by wind tunnel test and in-site measurement of long-span spatial structure

  • Liu, Hui;Qu, Wei-Lian;Li, Qiu-Sheng
    • Wind and Structures
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    • v.14 no.4
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    • pp.301-319
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    • 2011
  • The full-scale measurements are compared with the wind tunnel test results for the long-span roof latticed spatial structure of Shenzhen Citizen Center. A direct comparison of model testing results to full-scale measurements is always desirable, not only in validating the experimental data and methods but also in providing better understanding of the physics such as Reynolds numbers and scale effects. Since the quantity and location of full-scale measurements points are different from those of the wind tunnel tests taps, the weighted proper orthogonal decomposition technique is applied to the wind pressure data obtained from the wind tunnel tests to generate a time history of wind load vector, then loads acted on all the internal nodes are obtained by interpolation technique. The nodal mean wind pressure coefficients, root-mean-square of wind pressure coefficients and wind pressure power spectrum are also calculated. The time and frequency domain characteristics of full-scale measurements wind load are analyzed based on filtered data-acquisitions. In the analysis, special attention is paid to the distributions of the mean wind pressure coefficients of center part of Shenzhen Citizen Center long-span roof spatial latticed structure. Furthermore, a brief discussion about difference between the wind pressure power spectrum from the wind tunnel experiments and that from the full-scale in-site measurements is compared. The result is important fundament of wind-induced dynamic response of long-span spatial latticed structures.

A 6 m cube in an atmospheric boundary layer flow -Part 1. Full-scale and wind-tunnel results

  • Hoxey, R.P.;Richards, P.J.;Short, J.L.
    • Wind and Structures
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    • v.5 no.2_3_4
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    • pp.165-176
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    • 2002
  • Results of measurements of surface pressure and of velocity field made on a full-scale 6 m cube in natural wind are reported. Comparisons are made with results from boundary-layer wind-tunnel studies reported in the literature. Two flow angles are reported; flow normal to a face of the cube (the $0^{\circ}$ case) and flow at $45^{\circ}$. In most comparisons, the spread of wind-tunnel results of pressure measurements spans the full-scale measurements. The exception to this is for the $0^{\circ}$ case where the roof and side-wall pressures at full-scale are more negative, and as a result of this the leeward wall pressures are also lower. The cause of this difference is postulated to be a Reynolds Number scale effect that affects flow reattachment. Measurements of velocity in the vicinity of the cube have been used to define the mean reattachment point on the roof centre line for the $0^{\circ}$ case, and the ground level reattachment point behind the cube for both $0^{\circ}$ and $45^{\circ}$ flow. Comparisons are reported with another full-scale experiment and also with wind-tunnel experiments that indicate a possible dependency on turbulence levels in the approach flow.

Identification of flutter derivatives from full-scale ambient vibration measurements of the Clifton Suspension Bridge

  • Nikitas, Nikolaos;Macdonald, John H.G.;Jakobsen, Jasna B.
    • Wind and Structures
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    • v.14 no.3
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    • pp.221-238
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    • 2011
  • The estimated response of large-scale engineering structures to severe wind loads is prone to modelling uncertainties that can only ultimately be assessed by full-scale testing. To this end ambient vibration data from full-scale monitoring of the historic Clifton Suspension Bridge has been analysed using a combination of a frequency domain system identification method and a more elaborate stochastic identification technique. There is evidence of incipient coupling action between the first vertical and torsional modes in strong winds, providing unique full-scale data and making this an interesting case study. Flutter derivative estimation, which has rarely previously been attempted on full-scale data, was performed to provide deeper insight into the bridge aerodynamic behaviour, identifying trends towards flutter at higher wind speeds. It is shown that, as for other early suspension bridges with bluff cross-sections, single-degree-of-freedom flutter could potentially occur at wind speeds somewhat below requirements for modern designs. The analysis also demonstrates the viability of system identification techniques for extracting valuable results from full-scale data.

The influence of model surface roughness on wind loads of the RC chimney by comparing the full-scale measurements and wind tunnel simulations

  • Chen, Chern-Hwa;Chang, Cheng-Hsin;Lin, Yuh-Yi
    • Wind and Structures
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    • v.16 no.2
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    • pp.137-156
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    • 2013
  • A wind tunnel test of a scaled-down model and field measurement were effective methods for elucidating the aerodynamic behavior of a chimney under a wind load. Therefore, the relationship between the results of the wind tunnel test and the field measurement had to be determined. Accordingly, the set-up and testing method in the wind tunnel had to be modified from the field measurement to simulate the real behavior of a chimney under the wind flow with a larger Reynolds number. It enabled the results of the wind tunnel tests to be correlated with the field measurement. The model surface roughness and different turbulence intensity flows were added to the test. The simulated results of the wind tunnel test agreed with the full-scale measurements in the mean surface pressure distribution behavior.

Verification of Propeller-Induced Fluctuating Pressure in Sea Trials (실선에서의 프로펠러 변동압력 성능 검증)

  • Song In-Haeng;Seo Jongsoo;Paik Kwangjun;Jung Jaekwon
    • Special Issue of the Society of Naval Architects of Korea
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    • pp.44-50
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    • 2005
  • Since a cavitation pattern in model scale can be different from that in full scale, it has been highly demanded to measure a fluctuating pressure induced by propeller in full scale. For the verification of the cavitation test for 105K lanker in the large cavitation tunnel in Samsung Ship Model Basin(SSMB), an effective pressure fluctuation measurement system was developed and a series of full scale measurements was carried out. These results were compared with those of cavitation tests in SSMB. The measured results in full scale gave good agreements to those in model tests. The fluctuating pressure at $2^{nd}$ blade frequency in full scale seems to be highly dependent upon tip loading.

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Peak pressures on low rise buildings: CFD with LES versus full scale and wind tunnel measurements

  • Aly, Aly Mousaad;Gol-Zaroudi, Hamzeh
    • Wind and Structures
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    • v.30 no.1
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    • pp.99-117
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    • 2020
  • This paper focuses on the processes of wind flow in atmospheric boundary layer, to produce realistic full scale pressures for design of low-rise buildings. CFD with LES turbulence closure is implemented on a scale 1:1 prototype building. A proximity study was executed computationally in CFD with LES that suggests new recommendations on the computational domain size, in front of a building model, apart from common RANS-based guidelines (e.g., COST and AIJ). Our findings suggest a location of the test building, different from existing guidelines, and the inflow boundary proximity influences pressure correlation and reproduction of peak loads. The CFD LES results are compared to corresponding pressures from open jet, full scale, wind tunnel, and the ASCE 7-10 standard for roof Component & Cladding design. The CFD LES shows its adequacy to produce peak pressures/loads on buildings, in agreement with field pressures, due to its capabilities of reproducing the spectral contents of the inflow at 1:1 scale.

Comparative Study of Full-Scale Propeller Cavitation Test and LCT Model Test for MR Tanker (MR Tanker 실선 프로펠러 캐비테이션 시험 및 LCT 모형시험과 비교연구)

  • Ahn, Jong-Woo;Paik, Bu-Geun;Seol, Han-Shin;Park, Young-Ha;Kim, Gun-Do;Kim, Ki-Sup;Jung, Bo-Jun;Choi, Sung-Jun
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.3
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    • pp.171-179
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    • 2016
  • In order to study correlation of the propeller cavitation performance between a full-scale ship and a model ship for the MR Tanker, the full-scale ship and the model tests were conducted. The full-scale ship test is composed of cavitation observation, pressure fluctuation and noise measurements, which are conducted using 2 observation windows and 8 pressure transducers installed inside the full-scale ship above the propeller. The model test in the Large Cavitation Tunnel(LCT) was conducted at the same conditions as that of the full-scale ship and its results are compared with those of the full-scale ship. Through the model-ship correlation analysis, it is considered that the experimental technique for the MR Tanker class ship was verified in LCT.

The development of a field measurement instrumentation system for low-rise construction

  • Porterfield, Michelle L.;Jones, Nicholas P.
    • Wind and Structures
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    • v.4 no.3
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    • pp.247-260
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    • 2001
  • In the last three decades several comprehensive field measurement programs have produced significant insight into the wind effects on low-rise structures. The most notable and well published of these efforts are measurements being collected at the Wind Engineering Field Laboratory (WERFL) at Texas Tech University, measurements on low-rise structures in Silsoe, England and measurements on groups of low-rise structures collected in Aylesbury, England. Complementary to these efforts, an additional full-scale field investigation program has recently collected meteorological, pressure, strain and displacement data on a low-rise structure in Southern Shores, North Carolina. To date over seventy-five hundred data sets have been collected at the Southern Shores site in a variety meteorological conditions up to and including hurricane-force winds. This paper provides details of the system, its development, and preliminary assessment of its performance. A description of the field site, the instrumented structure, and the instrumentation system is provided. In addition, an example of the data collected during three hurricanes is presented. The primary goal of this paper is to provide the reader with the necessary technical details to appropriately interpret data from this experiment, which will be presented in future publications currently under development.

Performance Trial-Test of the Full-Scale Driving Pump for the Large Cavitation Tunnel(LCT) (대형캐비테이션터널(LCT) 실물 구동펌프 성능시운전)

  • Ahn, Jong-Woo;Kim, Gun-Do;Kim, Ki-Sup;Park, Young-Ha
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.6
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    • pp.428-434
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    • 2015
  • The objective of the present study is to analyze the results of the trial-test for the full-scale driving pump, which is arranged in the LCT (Large Cavitation Tunnel). Firstly, the reasons of selecting the final design pump are introduced in terms of the performance analysis in model tests. The trial-test items for the full-scale driving pump are measurements of output current/voltage at the inverter of the main motor and the flow velocity in the LCT test section. The test results show the increase in flow rate of about 10.7% and the decrease in pump head of about 26%, compared with those of final design-pump specification. The motor power has the margin of about 22%. The performance analysis for the full-scale pump is conducted using the commercial code (CFX-10). The delivered power calculated with CFX-10 shows good agreement with that extracted from the full-scale pump test. It is found that CFX-10 is useful to analyze a full-scale pump.

Measured Performance of Full Scale Tieback Walls in

  • Kim, Nak
    • Geotechnical Engineering
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    • v.14 no.3
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    • pp.5-24
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    • 1998
  • Two instrumented full scale tieback walls in sand were constructed at to Geotechnical Experimentation Site located on the Texas A 51M University Riversic Measurements were obtained from the one row anchor wall and from the two row at different times during construction. The measured performance of the tieback walls is presented and investigated. The these walls at different construction stage is evaluated with respect to lateral wall. settlement of the ground, bending moment of the wall. axial load distribution and anchor load variation. The fundamental mechanism of a tieback wall in sand is and explained with the measurements.

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