Effect of turbulent boundary layer induced coherence loss on beamforming measurements in industrial scale wind tunnel tests

2019 ◽  
Author(s):  
Julian Biesheuvel ◽  
Marthijn Tuinstra ◽  
Leandro D. de Santana ◽  
Kees Venner
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Turbulent Boundary Layer ◽  
Industrial Scale ◽  
Wind Tunnel Tests

Wind Tunnel Tests of Two Lucy Ashton Reflex Geosims

1970 ◽  
Vol 14 (04) ◽  
pp. 241-276
Author(s):  
P. N. Joubert ◽  
N. Matheson
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Turbulent Boundary Layer ◽  
Flat Plate ◽  
Skin Friction ◽  
Viscous Drag ◽  
Two Dimensional ◽  
Local Skin ◽  
Wind Tunnel Tests ◽  
Local Skin Friction

A 9-ft and a 4½-ft reflex model of the Lucy Ashton were tested in a wind tunnel. Both pins and wires were used as stimulators to promote a turbulent boundary layer. The effects of the stimulators could be taken into account by considering the virtual origin of the turbulent boundary layer. Slightly different viscous drag curves were found for each model, both with a slope much steeper than previously anticipated. The skin friction was determined using two independent methods. Large increases and deficits in local skin friction coefficients were found at the bow and stern of the models respectively as compared with those for a two-dimensional flat plate.

Predicting Wind Loads on the Topside of a Self-Propelled Wind Turbine Installation Jack-Up Using CFD

2021 ◽  
Author(s):  
Zana Sulaiman
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Full Range ◽  
Design Tool ◽  
Wind Loads ◽  
Computational Domain ◽  
Wind Tunnel Tests ◽  
Jack Up ◽  
Turbine Installation

Abstract This paper presents the results of wind load computational fluid dynamics (CFD) calculations performed on the topside structures of a self-propelled wind turbine installation jack-up. The CFD calculations were performed for the jack-up topside structures with and without the deck load. An atmospheric boundary layer profile was applied for the model-scale calculations. The full range of heading angles was considered. The CFD results were validated through comparison with the wind tunnel tests which were carried out at the German-Dutch wind tunnels (DNW) in Marknesse, The Netherlands. Moreover, a comparison is presented between the applied boundary layer profiles throughout the CFD computational domain with those profiles measured in the wind tunnel. The CFD results were found to be in good agreement with the wind tunnel tests for the considered cases, verifying the feasibility of the CFD method as an important design tool for the prediction of wind loads during the design processes of these types of jack-ups.

Some Observations on dr. Coleman's Comments

1957 ◽  
Vol 61 (557) ◽  
pp. 361-361
Author(s):  
G. V. Lachmann
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Short Distance ◽  
Wind Tunnel Tests ◽  
Theoretical Methods ◽  
Unit Reynolds Number ◽  
Research Department ◽  
Boundary Layer Profile

The method referred to in Dr. Coleman's notes was developed with the collaboration of my colleague Mr. J. B. Edwards of Handley Page Research Department. The purpose was to obtain a rational estimate of suction quantities and suction distribution, linked up with measurements of boundary layer profiles and suction quantities on wind tunnel models, and also to assess the effect of a certain degree of roughness of the order to be expected on actual wings. Existing theoretical methods ignore roughness which, however, is a most important parameter not only in wind tunnel tests, but also in flight at higher values of the unit Reynolds number; surface roughness obviously limits the intensity of suction which can be applied at a spanwise suction strip.It was intuitively assumed that the removal of fluid by suction was equivalent to cutting off the lower portion of the boundary layer profile at the upstream edge of the suction strip and that a rapid re-adjustment of the boundary layer profile within a short distance took place.

Aeromechanic Response of a Coupled Inlet-Fan Boundary Layer Ingesting Distortion-Tolerant Fan

2019 ◽  
Author(s):  
G. S. Heinlein ◽  
M. A. Bakhle ◽  
J. P. Chen
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Fluid Dynamic ◽  
Single Mode ◽  
Forced Response ◽  
Blade Vibration ◽  
Wind Tunnel Tests ◽  
Aerodynamic Damping ◽  
Insight Into ◽  
Tip Displacement

Abstract Boundary layer ingestion has significant potential to reduce fuel burn in aircraft engines. However, designing a fan that can operate in an environment of continuous distortion without aeromechanical failure is a critical challenge. Capturing the requisite aeromechanical flow features in a high-fidelity computational setting is necessary in validating satisfactory designs as well as determining possible regions for overall improvement. In the current work, a three-dimensional, time-accurate, Reynolds-averaged Navier-Stokes computational fluid dynamic code is utilized to study a distortion-tolerant fan coupled to a boundary layer ingesting inlet. The comparison between this coupled inlet-fan and a previous fan-only simulation will provide insight into the changes in aeromechanic response of the fan blades. Additionally, comparisons to previous wind tunnel tests are made to provide validation of inlet distortion as seen by the distortion-tolerant fan. A resonant crossing was also investigated for the 85% speed operational line condition to compare resonant response between the inlet-fan, fan-only, and experiment. A decrease in maximum tip displacement is observed in the forced response of the coupled inlet-fan compared to the fan-only simulation. The predicted maximum tip displacement was still below the upper limit on the range observed in the wind tunnel tests but matched well with the average tip displacement value of 27.6 mils. A single mode was chosen at the 100% speed condition to provide insight into the effects that the inlet duct has on fan stability. Near stall and near choke conditions were also simulated to observe how the changes of progressing along the speed line affects flutter stability prediction. The analysis shows the fan has low levels of aerodynamic damping at all the conditions tested. However, the coupled inlet-fan shows a decrease in the level of aerodynamic damping over what was observed with the fan-only simulation. Some of the blades experienced single cycles of negative aerodamping which indicate a possibility of increased blade vibration amplitude but were followed by positive aerodamping cycles. Work is continuing to understand possible sources to account for the differences observed between the two simulation cases as well as with the experiment.

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