Configuration design studies and wind tunnel tests of an energy efficient transport with a high-aspect-ratio supercritical wing

The results of design studies and wind tunnel tests of high aspect ratio supercritical wings suitable for a medium range, narrow body transport aircraft flying near M=0.80 were presented. The basic characteristics of the wing design were derived from system studies of advanced transport aircraft where detailed structural and aerodynamic tradeoffs were used to determine the most optimum design from the standpoint of fuel usage and direct operating cost. These basic characteristics included wing area, aspect ratio, average thickness, and sweep. The detailed wing design was accomplished through application of previous test results and advanced computational transonic flow procedures. In addition to the basic wing/body development, considerable attention was directed to nacelle/plyon location effects, horizontal tail effects, and boundary layer transition effects. Results of these tests showed that the basic cruise performance objectives were met or exceeded

An experimental study of transonic flow about a supercritical airfoil

A series of experiments was conducted on flow fields about two airfoil models whose sections are slight modifications of the original Whitcomb supercritical airfoil section. Data obtained include surface static-pressure distributions, far-wake surveys, oil-flow photographs, pitot-pressure surveys in the viscous regions, and holographic interferograms. These data were obtained for different combinations of lift coefficient and free-stream Mach number, which included both subcritical cases and flows with upper-surface shock waves. The availability of both pitot-pressure data and density data from interferograms allowed determination of flow-field properties in the vicinity of the trailing edge and in the wake without recourse to any assumptions about the local static pressure. The data show that significant static-pressure gradients normal to viscous layers exist in this region, and that they persist to approximately 10% chord downstream of the trailing edge. Comparisons are made between measured boundary-layer properties and results from boundary-layer computations that employed measured static-pressure distributions, as well as comparisons between data and results of airfoil flow-field computations

Using resistivity measurements for dam safety evaluation at Enemossen tailings dam in southern Sweden

Internal erosion is a major reason for embankment dam failures. Resistivity measurements is an essentially non-destructive technique, which may have the possibility of detecting internal erosion processes and anomalous seepage at an early stage before the safety of the dam is at stake. This paper presents results from part of a dam safety investigation conducted at the Enemossen tailings dam in southern Sweden. Longitudinal resistivity sections, 2D measurements along the dam crest, provided an overview of the whole dam and served to detect anomalous zones. In selected areas, additional cross-sectional 2D surveys gave detailed information about the geo-electrical situations in the embankments. This information is valuable for similar investigations as information about resistivity in embankment construction material is scarce. Known problem areas were associated with low resistivities, even though the resistivity measurements alone did not provide enough information to confidently come to a decision about the status of the dams

An experimental study of transonic flow about a supercritical airfoil. Static pressure and drag data obtained from tests of a supercritical airfoil and an NACA 0012 airfoil at transonic speeds, supplement

Surface static-pressure and drag data obtained from tests of two slightly modified versions of the original NASA Whitcomb airfoil and a model of the NACA 0012 airfoil section are presented. Data for the supercritical airfoil were obtained for a free-stream Mach number range of 0.5 to 0.9, and a chord Reynolds number range of 2 x 10 to the 6th power to 4 x 10 to the 6th power. The NACA 0012 airfoil was tested at a constant chord Reynolds number of 2 x 10 to the 6th power and a free-stream Mach number range of 0.6 to 0.8

Using the resistivity method for leakage detection in a blind test at the Rossvatn embankment dam test facility in Norway

Internal erosion is a cause of embankment dam failure, thus it is important to develop methods for seepage monitoring and internal erosion detection. In order to evaluate the potential of resistivity monitoring to give an early warning of such leakage/erosion, a test was undertaken on a rockfill embankment dam with a central glacial till core at the Rossvatn test facility in Norway. Three defects, consisting of permeable material, were built into the dam at various depths and locations unknown to the personnel carrying out the measurements and data interpretation. A numerical modelling pre-study was carried out, showing that all the actually constructed defects were too small to be detected by single time investigation. In the final test, repeated measurements were undertaken with different reservoir levels, i.e. a limited monitoring approach. This increased the detection capability, confirming the value of the geophysical approach and that monitoring is superior to single time investigations

Impact of smoking and preoperative electrophysiology on outcome after open carpal tunnel release

Background: The aim was to evaluate the influence of smoking and preoperative electrophysiology on the outcome of open carpal tunnel release. Methods: This retrospective observational study evaluated the outcome in 493 patients (531 hands) primary operated for carpal tunnel syndrome. Data were collected from medical records, health evaluations, and QuickDASH questionnaires before surgery and 1 year after. Results: Smokers had a higher QuickDASH score preoperatively as well as postoperatively, but the change in total score did not differ. The odds of having a postoperative QuickDASH score >10 were 2.5 times higher in smoking patients than in non-smoking patients. In 124/493 patients (25%), no clinically significant improvement was seen. Normal and extreme preoperative electrophysiology values were associated with higher postoperative scores. No correlation was found between preoperative QuickDASH scores and preoperative electrophysiology values. Conclusions: Smokers with carpal tunnel syndrome experience more symptoms preoperatively. Smokers have remaining symptoms after surgery. There is no correlation between preoperative QuickDASH scores and preoperative electrophysiology values. Patients with normal or near to normal preoperative electrophysiology results have limited improvement after surgery

Outcome after carpal tunnel release : impact of factors related to metabolic syndrome

Objective: The standard surgical treatment of carpal tunnel syndrome (CTS), with an open carpal tunnel release, is reported to relieve symptoms in most patients. In a retrospective observational study, outcome after open carpal tunnel release was evaluated, focusing on factors related to the metabolic syndrome: diabetes, hypertension, obesity (BMI ≥30) and statin treatment. Methods: Results from 493 out of 962 patients (531/1044 hands) operated for CTS during 18 months that had filled in QuickDASH questionnaires before and 1-year after surgery were included in the study. Results: Patients with diabetes (n = 76) had higher QuickDASH scores pre- (56 [36–77]; i.e. median [interquartile range]) and postoperatively (31 [9–61]) compared to patients without diabetes (48 [32–66]; p 10 (74% vs 61%;

Resistivity monitoring for leakage and internal erosion detection at Hallby embankment dam

Internal erosion is one of the major reasons for embankment dam failures. Despite this, the knowledge of the temporal development of internal erosion in full scale structures is limited. Detection of internal erosion is complicated using conventional methods, and new or improved methods are appreciated. Hallby was the first Swedish embankment to get a permanently installed monitoring system intended for resistivity measurements. Daily measurements started to take place already in late 1996, which make these long term monitoring data unique. This paper includes examples of long term time series from Hallby along with some evaluation and interpretation techniques used when analysing such monitoring data. Time-lapse inversion was used to focus the variation over time and suppress artefacts due to the resistivity structure. Seasonal resistivity variations inside the dam are obvious. Increasing long term resistivity has been noticed in a particular zone in the left embankment. This zone also exhibits larger seasonal variations relative to other parts of the dam, and the variations are increasing. The observations may relate to an ongoing internal erosion process in the dam. The long term change may be indicative of a change in material properties, and the large and increasing variations may reflect higher and increasing seepage levels. In the years 2004 to 2006 the dam was upgraded and the resistivity system reinstalled. The results indicate that resistivity monitoring may have a chance of detecting development of internal erosion at an early stage. (C) 2008 Published by Elsevier B.V