1,020 research outputs found
Selected experiments in laminar flow: An annotated bibliography
Since the 1930s, there have been attempts to reduce drag on airplanes by delaying laminar to turbulent boundary layer transition. Experiments conducted during the 1940's, while successful in delaying transition, were discouraging because of the careful surface preparation necessary to meet roughness and waviness requirements. The resulting lull in research lasted nearly 30 years. By the late 1970s, airframe construction techniques had advanced sufficiently that the high surface quality required for natural laminar flow (NLF) and laminar flow control (LFC) appeared possible on production aircraft. As a result, NLF and LFC research became widespread. This report is an overview of that research. The experiments summarized herein were selected for their applicability to small transonic aircraft. Both flight and wind tunnel tests are included. The description of each experiment is followed by corresponding references. Part One summarizes NLF experiments; Part Two deals with LFC and hybrid laminar flow control (HLFC) experiments
Democratization of Ocean Research: A Model for the Post-Cold War Era?
Since the end of World War II the field of oceanography has enjoyed the generous patronage of the federal government under the social contract model for the support of science. This model is based on the principles of freedom and autonomy for scientists, insulation of science from politics, and emphasis on basic research. With the recent ending of the Cold War, the simple science policies of the post-World War II years are being philosophically and politically challenged and the rationales for the support of science are being questioned. National security is no longer the driving force behind science funding in the United States. With a heavy dependence on the federal government for support and strong roots in the Cold War, oceanographic science is particularly vulnerable at this time to shifts in national priorities. Calls have been made for the negotiation of a new social contract between scientists and the federal government. In this paper a model for a new social contract is suggested based on the democratization of science. Indicators of democratization are presented and data relevant to the oceanographic field are analyzed. It is concluded that a shift is underway toward the democratization of academic oceanography in the United States in the post-Cold War era
Assessing Impact of Online Delivery of Turfgrass and Landscape Information
Kansas State University\u27s turfgrass Extension team delivers information via linked online resources that include a blog, emails, and social media. We recently surveyed users to assess who they are, what they learn, how they use information, overall impressions, as well as suggested improvements. Users learn how to identify and manage various pests, select plant materials, and where to access further information and training. They prefer an email as the portal to the information. They communicate the information with others. Survey respondents suggested several revisions to format and content
Transonic wind tunnel test of a 14 percent thick oblique wing
An experimental investigation was conducted at the ARC 11- by 11-Foot Transonic Wind Tunnel as part of the Oblique Wing Research Aircraft Program to study the aerodynamic performance and stability characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing designed by Rockwell International. The 10.3 aspect ratio, straight-tapered wing of 0.14 thickness/chord ratio was tested at two different mounting heights above the fuselage. Additional tests were conducted to assess low-speed behavior with and without flaps, aileron effectiveness at representative flight conditions, and transonic drag divergence with 0 degree wing sweep. Longitudinal stability data were obtained at sweep angles of 0, 30, 45, 60, and 65 degrees, at Mach numbers ranging from 0.25 to 1.40. Test Reynolds numbers varied from 3.2 to 6.6 x 10 exp 6/ft. and angle of attack ranged from -5 to +18 degrees. Most data were taken at zero sideslip, but a few runs were at sideslip angles of +/- 5 degrees. The raised wing position proved detrimental overall, although side force and yawing moment were reduced at some conditions. Maximum lift coefficient with the flaps deflected was found to fall short of the value predicted in the preliminary design document. The performance and trim characteristics of the present wing are generally inferior to those obtained for a previously tested wing designed at ARC
CPIES Data Collected Near Hydrostation S Southeast of Bermuda from June 2016 to June 2017
This report focuses on data collected from four current meter equipped pressure inverted echo sounders (CPIES), two with respectively two and one Popeye Data Shuttles (PDS) on them, and two dual-pressure CPIES each with a Paroscientific stable oceanographic sensor (SOS) and a 46K sensor that has a long track record of previous deployments with low-drift, deployed from June 2016 to June 2017 near Hydrostation S, 25 km southeast of Bermuda (Figure 1). The CPIES were moored at similar depths, ranging from approximately 3400 to 3600 m, at sites numbered clockwise around Hydrostation S as P1, P2, P3, and P4
An Intercomparison of Four Models of Current Meter in High Current Conditions in Drake Passage
Seven current meters representing four models were placed for an 11 month deployment on a stiffly buoyed mooring to intercompare their velocity measurements: two VMCMs, two Aanderaa RCM11s, two Aanderaa SEAGUARDSs, and a Nortek Aquadopp. The current meters were placed 6 m apart from each other at about 4000 m depth in an area of Drake Passage expected to have strong near-bottom currents, that were nearly independent of depth. Two high-current events occurred in bursts of semi-diurnal pulses lasting several days, one with peak speeds up to 67 cm/s and the other above 35 cm/s. The current speed measurements all agreed within about 5% when vector-averaged over simultaneous time intervals: the full time interval (198 days) when all instruments were working, and the two high-speed events lasting 21 days and 7 days. The VMCMs, chosen as the reference measurements, were found to measure the median of the mean-current magnitudes. The RCM11 and SEAGUARD current speeds had a nearly 1:1 relationship with the median. They agreed within 2% at higher speeds (35-70 cm/s), whereas in lower speed ranges (0-35 cm/s) the vector-averaged speeds for the RCM11s and SEAGUARDS were, respectively, 4-5% lower and 3-5% higher than the median. The Aquadopp current speeds were about 7% higher than the VMCMs over the range (0-40 cm/s) encountered through their shorter common time period
Multidimensional analogs of geometric s<-->t duality
The usual propetry of st duality for scattering amplitudes, e.g. for
Veneziano amplitude, is deeply connected with the 2-dimensional geometry. In
particular, a simple geometric construction of such amplitudes was proposed in
a joint work by this author and S.Saito (solv-int/9812016). Here we propose
analogs of one of those amplitudes associated with multidimensional euclidean
spaces, paying most attention to the 3-dimensional case. Our results can be
regarded as a variant of "Regge calculus" intimately connected with ideas of
the theory of integrable models.Comment: LaTeX2e, pictures using emlines. In this re-submission, an English
version of the paper is added (9 pages, file english.tex) to the originally
submitted file in Russian (10 pages, russian.tex
PIES and CPIES Data Processing Manual
The Inverted Echo Sounder (IES) is an ocean bottom-moored instrument that measures the vertical acoustic travel time (VATT) round-trip from the seafloor to the sea surface and back. The VATT varies principally due to changes in the temperature profile of the water column, making the IES well-suited for monitoring changes in temperature structure and dynamic height (baroclinic signal). Currently, the Model 6.2, a combined IES, data-logger, and acoustic release, with measurements of bottom pressure and temperature (PIES) and optional measurements of current speed and direction (CPIES, with attached Aanderaa Doppler current sensor) is produced at URI/GSO. Data are processed in situ and are available (optional) remotely by an acoustic telemetry link. In addition to the IES-measured baroclinic signals, barotropic near-bottom pressure variations may be measured with the optional pressure sensor. A report was written in 1991 describing IES data processing [Fields et al., 1991]. Since that report, significant improvements have been made to both IES hardware and software, warranting an update of the IES data processing. The report by Kennelly et al. [2007] documents the standard processing steps contained in IESpkg 3, which has been used since the early 2000s, for IES/PIES/CPIES Models 6.1 and 6.2 at URI/GSO. More recently, IESpkg 4 was developed to allow more flexibility in the processing steps and data outputs, and to process the Fast PIES versions that sample 96 travel times each hour. This report documents the processing steps in IESpkg 4 and it repeats as much of the original text of Kennelly et al. [2007] as is still applicable. A separate document, Inverted Echo Sounder User\u27s Manual, IES Model 6.2, describes the IES hardware and instrument configuratio
- …