Wind tunnel evaluation of a truncated NACA 64-621 airfoil for wind turbine applications

An experimental program to measure the aerodynamic performance of a NACA 64-621 airfoil with a truncated trailing edge for wind turbine applications has been conducted in the Ohio State University Aeronautical and Astronautical Research Laboratory 6 in. by 21 in. pressurized wind tunnel. The blunted or trailing edge truncated (TET) airfoil has an advantage over similar trailing edge airfoils because it is able to streamline a larger spar structure, while also providing aerodynamic properties that are quite good. Surface pressures were measured and integrated to determine the lift, pressure drag, and moment coefficients over angles of attack ranging from -14 to +90 deg at Mach 0.2 and Reynolds numbers of 1,000,000 and 600,000. Results are compared to the NACA 0025, 0030, and 0035 thick airfoils with sharp trailing edges. Comparison shows that the 30 percent thick NACA 64-621-TET airfoil has higher maximum lift, higher lift curve slope, lower drag at higher lift coefficients, and higher chordwise force coefficient than similar thick airfoils with sharp trailing edges

Propeller aeroacoustic methodologies

The aspects related to propeller performance by means of a review of propeller methodologies are addressed. Preliminary wind tunnel propeller performance data are presented and the predominent limitations of existing propeller performance methodologies are discussed. Airfoil developments appropriate for propeller applications are also reviewed

A hypersonic research vehicle to develop scramjet engines

Four student design teams produced conceptual designs for a research vehicle to develop the supersonic combustion ramjet (scramjet) engines necessary for efficient hypersonic flight. This research aircraft would provide flight test data for prototype scramjets that is not available in groundbased test facilities. The design specifications call for a research aircraft to be launched from a carrier aircraft at 40,000 feet and a Mach number of 0.8. The aircraft must accelerate to Mach 6 while climbing to a 100,000 foot altitude and then ignite the experimental scramjet engines for acceleration to Mach 10. The research vehicle must then be recovered for another flight. The students responded with four different designs, two piloted waverider configurations, and two unmanned vehicles, one with a blended body-wing configuration, the other with a delta wing shape. All aircraft made use of an engine database provided by the General Electric Aircraft Engine Group; both turbofan ramjet and scramjet engine performance using liquid hydrogen fuel was available. Explained here are the students' conceptual designs and the aerodynamic and propulsion concepts that made their designs feasible

Two-dimensional aerodynamic characteristics of the AMES HI-120, HI-8, and LOW-12 airfoils

During the period between June and September 1986, the Aeronautical and Astronautical Engineering Research Laboratory (AARL) at the Ohio State University (OSU) in Columbus, Ohio, conducted tests in the 6"X22" Transonic Blowdown Wind Tunnel to determine the two-dimensional lift, drag, and pitching moment coefficients for three airfoils designated AMES HI-120, AMES LOW-12, and AMES HI-8. These tests covered a Mach number range of 0.20 to 0.86, Reynolds numbers between 2 x 10 to the 6th and 6 x 10 to the 6th powers, and angles of attack between 0 and 13 degs as directed by the NASA Project Engineer; each model was not run at every condition. This work was performed under NASA Grant NAG-2-401, Analysis of Two Advanced Transonic Airfoils

THE ANATOMICAL RELATIONSHIPS, ULTRASTRUCTURE, AND FUNCTION OF THE PINEAL GLAND IN SOME COMMON LABORATORY RODENTS

The pineal complex of rodents is made up of a pineal organ which developmentally always originates from the area between the habenular and posterior commissure and a pineal sac which is continuous with the choroid plexus of the third ventricle. This sac appears to be identical to the choroid plexus at both light and electron microscopic levels. The pineal sac abuts the deep and superficial pineal organs of the golden hamster. In the PET mouse, gerbil, kangaroo rat and Chinese hamster, the sac is contiguous with only small areas of pinealocytes. This sac never abuts true pineal parenchyma in the albino rat. The variability of the relationship between this sac and pineal parenchyma indicates that this structure may not be the main physiological route of pineal gland secretion. The ultrastructure of pinealocytes from normal and blinded PET mice and normal and blinded gerbils indicate s the possibility of secretory activity in pinealocytes. Pinealocytes in the PET mouse have many dense core vesicles which can be found in the perykaryon, processes, and polar terminals of the cells which end in a pericapillary space. This space is near a fenestrated capillary. The possibility exists that these dense cored vesicles may be extruded from the cell terminals and pass into the fenestrated capillaries. Such fenestrated capillaries commonly are found in endocrine organs. The gerbil pinealocyte has two types of granules. Their nature is unknown, and the relationship between the two is uncertain. Small granules, resembling the small granules in gerbil pinealocytes in size and density, can be found in intercellular and pericapillary spaces. The relationships between these two granules is equally in doubt. The ultrastructure of pinealocytes of PET mice and gerbils reflects changes with blinding. Pinealocytes of blinded PET mice are more vesiculated and have greater numbers of lipid droplets. The pineal glands of those blinded gerbils, which were known to be highly functional by their physiological effects on the gonads, contained large electron dense structures. They were found in unidentified cell processes, interstitial cells, and pinealocytes. Pineal glands from a greater number of animals will have to be studied and compared with those of the same species reflecting low pineal activity in order to verify the relationship between pineal activity and these large electron dense structures. Histochemical analyses would be essential to identify and to clarify the relationships and activities among these vesicles, granules, and electron dense structures in pinealocytes of PET mice and gerbils. Blinding of the golden brown hamster and the gerbil resulted in a significant decrease of testis and seminal vesicle weight. This effect in the gerbil occurred during the fall season but when repeated during the winter season resulted only in the decrease of seminal vesicle weight. Female gerbils, however, responded to blinding by a decrease in ovarian and uterine weights during the winter season but only in uterine weight during the fall season. All of these effects of a lack of light on the gonads were prevented if the animals were also pinealectomized. The effects of olfactoriectomy which resulted in a decrease in seminal vesicle weight in one series of gerbils could also be overcome by pinealectomy. The pineal gland then may be responsible for production of an antigonadic substance. with the pineal gland removed the antigonadic source is removed, and the testis and/or seminal vesicle weights remain normal. A lack of light appears to stimulate the pineal gland to function since pinealectomy alone did not effect an increase in reproductive organ size in any of the animals which we studied. The albino rat and PET mouse did not respond to a lack of light as did the hamster and gerbil. Moreover, in the PET mouse, blindness did not affect prepubertal or postpubertal animals, adults during different seasons of the year, or adults treated neonatally with testosterone propionate. Female PET mice and male wild mice were equally unaffected. An effect of the pineal gland on the pituitary gland and adrenal gland is doubtful. Animals with or without a pineal gland exhibited no difference in pituitary or adrenal weights. More sensitive techniques will have to be employed to determine pineal-pituitary and pineal-adrenal interactions

An investigation of the aerodynamic characteristics of a new general aviation airfoil in flight

A low speed airfoil, the GA(W)-2, - a 13% thickness to chord ratio airfoil was evaluated. The wing of a Beech Sundowner was modified at by adding balsa ribs and covered with aluminum skin, to alter the existing airfoil shape to that of the GA(W)-2 airfoil. The aircraft was flown in a flight test program that gathered wing surface pressures and wake data from which the lift drag, and pitching moment of the airfoil could be determined. After the base line performance of the airfoil was measured, the drag due to surface irregularities such as steps, rivets and surface waviness was determined. The potential reduction of drag through the use of surface coatings such as KAPTON was also investigated

Comparative wind tunnel test at high Reynolds numbers of NACA 64 621 airfoils with two aileron configurations

An experimental program to measure the aerodynamic characteristics of the NACA 64-621 airfoil when equipped with plain ailerons of 0.38 chord and 0.30 chord and with 0.38 chord balanced aileron has been conducted in the pressurized O.S.U. 6 x 12 ft High Reynolds Number Wind Tunnel. Surface pressures were measured and integrated to yield lift and pressure drag coefficients for angles of attack from -3 to +42 deg and for selected aileron deflections from 0 to -90 deg at nominal Mach and Reynolds numbers of 0.25 and 5 x 10(exp 6). When resolved into thrust coefficient for wind turbine aerodynamic control applications, the data indicated the anticipated decrease in thrust coefficient with negative aileron deflection at low angles of attack; however, as angle of attack increased, thrust coefficients eventually became positive. All aileron configurations, even at -90 deg deflections showed this trend. Hinge moments for each configuration complete the data set

The use of platelet-rich plasma in osteoarthritis - the current state of knowledge

Introduction and objective: Osteoarthritis (OA) is a chronic condition characterized by progressive damage to the joint cartilage and bone. Platelet-rich plasma (PRP) has gained increasing interest as a potential therapeutic approach for relieving symptoms and improving joint function. The aim of this article is to present the current knowledge regarding the PRP preparation method, mechanisms of action, and treatment outcomes in OA based on scientific literature and recent research. Materials and methods: A review of scientific literature available on Google Scholar, PubMed, and Via Medica journal database was conducted using relevant keywords. State of knowledge: Platelet-rich plasma is obtained from the patient's own blood using differential centrifugation method, resulting in a concentration of platelets (PLT) that is 300-700% higher compared to the baseline. PLTs release various biologically active substances, including growth factors, which stimulate tissue repair and regeneration processes. Numerous studies have shown that PRP administration in patients with osteoarthritis of the knee and hip joints leads to pain reduction and improved joint function. The therapeutic effect yields long-lasting results, lasting up to 12 months after the completion of the treatment. Conclusions: The use of platelet-rich plasma (PRP) in the treatment of osteoarthritis presents a promising alternative to conventional therapies. However, further research is needed to confirm the effectiveness of PRP on a larger sample size and assess the long-term effects of this therapy. Knowledge regarding dosage, treatment protocols, and the duration of therapy remains limited

Analytical study of a free-wing/free-trimmer concept

The free-wing/free-trimmer is a NASA-Conceived extension of the free-wing concept intended to permit the use of high-lift flaps. Wing pitching moments are balanced by a smaller, external surface attached by a boom or equivalent structure. The external trimmer is, itself, a miniature free wing, and pitch control of the wing-trimmer assembly is effected through a trailing-edge control tab on the trimmer surface. The longitudinal behavior of representative small free-wing/free-trimmer aircraft was analyzed. Aft-mounted trimmer surfaces are found to be superior to forward trimmers, although the permissible trimmer moment arm is limited, in both cases, by adverse dynamic effects. Aft-trimmer configurations provide excellent gust alleviation and meet fundamental stick-fixed stability criteria while exceeding the lift capabilities of pure free-wing configurations