Air Intake Influence on the Test-section Flow Quality of an Open-Circuit Wind Tunnel

2005 ◽  
Author(s):  
Marcelo Assato ◽  
João Sena ◽  
Nide Fico ◽  
Roberto Girardi
Keyword(s):  
Wind Tunnel ◽  
Test Section ◽  
Open Circuit ◽  
Air Intake ◽  
Flow Quality

scholarly journals Measurementimprovement of flow quality of slotted test section in transonic wind tunnel

2021 ◽  
Vol 39 (3) ◽  
pp. 660-667
Author(s):  
Shenghao Wu ◽  
Jiming Chen ◽  
Qin Chen ◽  
Haitao Pei
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Test Section ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Area Ratio ◽  
Straight Section ◽  
Flow Quality ◽  
Transonic Wind Tunnel

Experimental studies were carried out in the 0.6 m×0.6 m continuous transonic wind tunnel of CARDC in order to investigate the flow characteristics of the slotted test section. Experimental results show that the root-mean-square deviation of axial Mach number in the model area is above 0.01 when the test section Mach number is above 1.0.Numerical simulation under the same conditions to investigate the flow characteristics of the slotted section, together with the experimental studies indicate tow phenomena may directly cause the Mach number fluctuation. Firstly, a straight section was installed to connect the nozzle and the test section in the wind tunnel. Weak shock waves due to the curvature discontinuity at the joint of the test section and the straight section contribute to Mach number fluctuation. Secondly, the open-area ratio of both the upper and lower wall of test section, each with 8 slots, is of 10%. The larger porosity leads to stronger expansion waves in the acceleration zone located at the inlet of the test section. The flow was over accelerated because of the stronger expansion wave and thus fluctuate the flow field severely. Two measures were taken to improve the flow quality of the slotted test section based on the above-mentioned analysis: ①Flexible plate instead of solid straight plate was installed to bridge nozzle and test section to eliminate the curvature discontinuity; ②Decreasing the open-area ratio of the upper and lower test section wall to 6% and the number of slots to 6. Numerical and experimental results show that the Mach number fluctuation in the model area was suppressed to a satisfactory degree.

scholarly journals Pengukuran Kualitas Kecepatan Angin pada Terowongan Angin di ILST BBTA3

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Novan Risnawan ◽  
F. Andree Yohanes ◽  
Sunarno Sunarno ◽  
Hetty Novianti ◽  
Yusron Feriadi
Keyword(s):  
Wind Tunnel ◽  
Test Section ◽  
Dynamic Pressure ◽  
Reference Value ◽  
Pitot Tube ◽  
Calibration Coefficient ◽  
Result Show ◽  
Flow Quality ◽  
Low Speed Wind Tunnel

AbstractCalibration check of Indonesia Low Speed Wind Tunnel (ILST) flow reference value have been performed at the beginning of 2018. Calibration check have been conducted to the calibration coefficient of predicted freestream static and dynamic pressure. This wind tunnel reference values is reffered to the static and dynamic pressure of a reference pitot tube that is installed at the center of turn table inside the test section. The test is conducted in empty test section. The calibration check result is very close to the previous values. This result show that flow quality of ILST wind tunnel is still maintained well for aerodynamic testing purposes.Keywords: Wind tunnel calibration, tunnel reference value. AbstrakPengecekan hasil kalibrasi besaran-besaran acuan aliran terowongan angin ILST telah selesai dilakukan pada awal tahun 2018. Pengecekan kalibrasi dilakukan terhadap koefisien kalibrasi tekanan statik dan tekanan dinamik terprediksi. Koefisien-koefisien referensi terowongan angin ini disesuaikan dengan tekanan statik dan tekanan dinamik yang dibaca oleh pitot tube acuan yang dipasang di tengah turn table di dalam seksi uji. Pengukuran dilakukan pada kondisi seksi uji kosong (empty test section). Hasil pengecekan kalibrasi acuan ini sangat dekat dengan hasil sebelumnya. Hasil kegiatan ini secara umum menunjukkan bahwa kualitas aliran terowongan angin ILST masih terpelihara dengan baik untuk keperluan pengujian aerodinamik.Kata Kunci : Kalibrasi terowongan angin, referensi terowongan angin. 

Air flow quality analysis of an open-circuit boundary layer wind tunnel and comparison with a closed-circuit wind tunnel

2020 ◽  
Vol 32 (12) ◽  
pp. 125120
Author(s):  
María Jiménez-Portaz ◽  
Luca Chiapponi ◽  
María Clavero ◽  
Miguel A. Losada
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Air Flow ◽  
Open Circuit ◽  
Closed Circuit ◽  
Quality Analysis ◽  
Flow Quality

Control of separation in the concave portion of contraction to improve the flow quality

2009 ◽  
Vol 113 (1141) ◽  
pp. 177-182 ◽  
Author(s):  
K. Ghorbanian ◽  
M. R. Soltani ◽  
M. D. Manshadi ◽  
M. Mirzaei
Keyword(s):  
Wind Tunnel ◽  
Pressure Distribution ◽  
Turbulence Intensity ◽  
Test Section ◽  
Adverse Pressure Gradient ◽  
Wind Tunnel Experiments ◽  
Free Stream Turbulence ◽  
Static Pressure Distribution ◽  
Subsonic Wind Tunnel ◽  
Flow Quality

AbstractSubsonic wind tunnel experiments were conducted to study the effect of forced transition on the pressure distribution in the concave portion of contraction. Further more, the effect of early transition on the turbulence level in the test section of the wind tunnel is studied. Measurements were performed by installing several trip strips at two different positions in the concave portion of the contraction. The results show that installation of the trip strips, have significant effects on both turbulence intensity and on the pressure distribution. The reduction in the free stream turbulence as well as the wall static pressure distribution varied significantly with the location of the trip strip. The results confirm the significant impact of the tripped boundary layer on the control of adverse pressure gradient. The trip strip atX/L= 0.115 improves pressure distribution in contraction and reduces turbulence intensity in the test section, considerably.

scholarly journals ANALISA DISTRIBUSI KECEPATAN ALIRAN OPEN CIRCUIT TYPE SUBSONIC WIND TUNNEL MENGGUNAKAN PIPA PITOT DENGAN PEMBACAAN SENSOR TEKANAN MPXV7002DP

2019 ◽  
Vol 2 (2) ◽  
pp. 57
Author(s):  
Muhamad Hanifudin
Keyword(s):  
Wind Tunnel ◽  
Test Section ◽  
Open Circuit ◽  
Subsonic Wind Tunnel

Tuntutan memiliki wind tunnel semakin tinggi di mana wind tunnel bermanfaat untuk mahasiswa teknik yang akan mengadakan penelitian lanjutan yang berkenaan dengan gaya-gaya aerodinamis (drag, lift, side), fenomena aliran udara ataupun tentang pengembangan terowongan angin itu sendiri. Atas dasar tersebut kami bermaksud merancang dan membangun wind tunnel.Sebelum wind tunnel dapat dipakai untuk pengujian gaya-gaya terhadap benda, diperlukan pengujian distribusi kecepatan aliran udara pada wind tunnel. Pengujian distribusi kecepatan aliran wind tunnel biasanya dilakukan dengan menggunakan pipa pitot pembacaan manometer pipa U. Untuk mendapatkan hasil pengukuran yang lebih akurat dan cepat maka pembacaan tekanan diganti dengan sensor tekanan dikombinasikan dengan arduino. Sehingga data yang diperoleh nantinya akan bisa dikonversi otomatis menjadi kecepatan aliran dengan menggunakan program arduino. Setelah dilakukan penelitian pengukuran kecepatan aliran udara dengan menggunakan pipa pitot dan sensor tekanan MPXV7002DP dikombinasikan Arduino hasilnya lebih cepat dan lebih akurat karena dapat mengukur kecepatan yang lebih rendah dibanding manometer pipa U yaitu 2.55 m/s dibanding 4.031 m/s . Akan tetapi jangkauan maksimalya tidak setinggi manometer pipa U karena hanya ternyata hanya mampu membaca kecepatan lebih dari 2.55 m/s sampai 57.64 m/s. Sedangkan manometer pipa U dapat membaca kecepatan lebih dari 57.64 m/s. Hasil pengujian kecepatan aliran udara pada wind tunnel didapatkan bahwa kececepatan minimal aliran udara yang melewati test section adalah 11.81 m/s sedangkan kececepatan maksimal aliran udara yang melewati test section adalah 12.72 m/s. Distribusi kecepatan aliran udara Open Circuit Type Subsonic Wind Tunnel dapat dikatakan seragam tapi belum baik karena setelah diuji dengan Peta I-MR kecepatan aliran masih melewati batas kontrol.

A Small Wind Tunnel Significantly Improved by a Multi-Purpose, Two-Flexible-Wall Test Section

1994 ◽  
Vol 116 (3) ◽  
pp. 419-423 ◽  
Author(s):  
P. Kankainen ◽  
E. Brundrett ◽  
J. A. Kaiser
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Test Section ◽  
Side Wall ◽  
Reynolds Numbers ◽  
Free Data ◽  
Wall Panels ◽  
Testing Data ◽  
Flexible Wall ◽  
Flow Quality

A small open-return wind tunnel has been renovated to include a longer test section with a flexible roof and floor and improved entrance flow quality. The flexible-wall test section allows models with up to 30 percent nominal blockage to be tested, resulting in a significant increase in the maximum attainable Reynolds numbers. Interchangeable rigid side-wall panels allow flexibility of application which is essential for a university wind tunnel facility. Configurations have been developed for automotive, aerodynamic and atmospheric-boundary-layer testing. Data acquisition and wall positioning are at an economical semi-automated level of operation. The flexible-wall concept has been well-documented previously, and provides interference-free data without flow pattern assumptions after a few iterations of the roof and floor shape. Representative data are presented for a circular cylinder and an airfoil.

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