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Showing papers on "Leading edge published in 1990"



Patent
04 Dec 1990
TL;DR: In this article, an anti-icing system for leading edges of an aircraft is described, where hot compressed air is discharged from a cavity behind the leading edge, through a multitude of small holes in the leading-edge skin into the airflow impinging on the leading edges.
Abstract: An anti-icing system for leading edges of an aircraft. Hot compressed air is discharged from a cavity behind the leading edge, through a multitude of small holes in the leading edge skin into the airflow impinging on the leading edge. In a first embodiment the anti-icing system utilizes part of the air distribution system in existence for a laminar flow control system. Instead of sucking air into the wing, as is done in the laminar flow control mode, the flow is reversed in the anti-icing mode, blowing hot compressed air out of the wing. In a second embodiment the anti-icing system is used solely in the anti-icing mode.

171 citations


Journal ArticleDOI
TL;DR: In this paper, the stator/rotor interaction in a highly loaded transonic first turbine stage is analyzed using time-incline d computational planes to allow the analysis of cases in which the ratio of stator and rotor pitches is not equal to unity or the ratios of two small integers.
Abstract: This paper presents calculations of a stator/rotor interaction in a highly loaded transonic first turbine stage. Of particular interest is the propagation and reflection of shocks which originate at the trailing edge of the upstream stator. These produce a 40% variation in the lift on the rotor, which would cause structural vibrations and increased losses. Also, the unsteady shocks would cause temporary boundary-layer separation near the leading edge of the suction surface. The numerical procedure solves the inviscid unsteady Euler equations, including quasi-three-dimensional terms. The use of a conservative treatment guarantees the correct treatment of the moving shocks. A simple technique is used to couple the calculations on the stator and rotor grids. A key feature of the paper is the use of "time-incline d" computational planes to allow the analysis of cases in which the ratio of stator and rotor pitches is not equal to unity or the ratio of two small integers.

169 citations


01 Jan 1990
TL;DR: In this paper, the amplitude of the leading edge of the a-wave of the human electroretinogram (ERG) was compared with predictions from a computational model of the light-induced responses of rod mammalian receptors.
Abstract: The amplitude of the leading edge of the a-wave of the human electroretinogram (ERG) was compared with predictions from a computational model of the light-induced responses of rod mammalian receptors. According to this model, a linear process describes the amplitude and time course of the response to relatively low flash intensities and at brief times after the onset of the flash. At higher flash intensities, a nonlinear process, described by the Naka-Rushton function or a saturating exponential, is involved. The primary focus here is on intensity-response data recorded with a clinical ganzfeld apparatus. The leading edge of the rod a-wave recorded from normal observers and patients with congenital stationary night blindness (CSNB) was described by a linear process for flash intensities up to the maximum available flash intensity, 2.0 log scot td-sec. This finding is consistent with the model of the rod's response. It suggests, however, that when ERGs are recorded with clinical systems limited to 2.0 log scot td-sec, these data cannot be used to distinguish between changes in the parameters (eg, semisaturation intensity versus maximum response) of the human rod receptors. Responses to flash intensities up to 3.4 log scot td-sec were recorded using a custom, high-intensity ganzfeld system. Both the linear and nonlinear components of the model were needed to fit the ERGs recorded with this system. This suggests that changes in different receptor parameters can be distinguished with higher intensity flashes. Invest Ophthalmol Vis Sci 31:2070-2081, 1990 The vertebrate electroretinogram (ERG) shows two prominent peaks in potential, the a- and b-waves. For over 50 years, the leading edge of the a-wave has been associated with receptor activity. 1 " 4 Uncertainty remains, however, about the answers to two basic questions. First, to what extent does the a-wave reflect receptor activity? For example, can we assume that the amplitude of the a-wave is linearly related to the size of the receptor's response? Second, can we associate specific defects in receptor function with alterations in the leading edge of the a-wave? In this report we address these questions by comparing the leading edge of the a-wave to responses predicted by a computational model of the rod receptor response. The amplitude of the leading edge of the a-wave varies with both the intensity of the flash and the time after the onset of the flash. The a-wave grows in amplitude during the first 30 msec or so of the ERG and is larger for more intense lights. To determine the relationship of the a-wave to rod receptor activity requires a model of the receptor's response that incorporates both the time course of the response and the

162 citations


Journal ArticleDOI
TL;DR: In this paper, the rotor-stator interaction within a centrifugal pump having several vaned diffusers, under conditions of different flow coefficients and different radial gaps between the impeller blade trailing edge and the diffuser vane leading edge, was investigated.
Abstract: Steady and unsteady diffuser vane pressure measurements have been conducted with a two-dimensional test impeller, in an experimental investigation of rotor-stator interaction within a centrifugal pump having several vaned diffusers, under conditions of different flow coefficients and different radial gaps between the impeller blade trailing edge and the diffuser vane leading edge. The largest pressure fluctuations on the diffuser vanes and the impeller blades were found to be of the same order of magnitude as the total pressure rise across the pump. Increasing the number of diffuser vanes was found to result in a significant decrease of impeller blade pressure fluctuations.

148 citations


Patent
12 Jan 1990
TL;DR: In this paper, an internally air cooled turbine blade for a gas turbine engine of the type including a trailing edge section, leading edge section and mid chord section is described, where each section includes a straight through radial passage communicating cooling air from the root to the tip of the blade, and the radial passages (feed channels) on the pressure side and suction side supply the cooling air to the film cooling holes in the airfoil surface.
Abstract: An internally air cooled turbine blade for a gas turbine engine of the type including a trailing edge section, leading edge section and mid chord section wherein each section includes a straight through radial passage communicating cooling air from the root to the tip of the blade, and the radial passages (feed channels) on the pressure side and suction side supply the cooling air to the film cooling holes in the airfoil surface and the radial passage (feed chamber) in the mid chord section replenishes the feed channels with cooling air through replenishment cooling holes interconnecting the feed channels and feed chamber The rotation of the blade imparts a centrifugal pumping action to the air within the feed chamber for maximizing the cooling effectiveness of the cooling air The air discharging at the tip cools the tip of the blade and provides tip aerodynamic sealing and the leading edge and trailing edge are similarly fed cooling air

140 citations


Journal ArticleDOI
TL;DR: In this article, a detailed comparison between the parallel and non-parallel theories is given and it is shown that at small vortex wavelengths, the parallel flow theories have some validity; unless the vortex wavelength is small, nonparallel effects are dominant.
Abstract: Goertler vortices are thought to be the cause of transition in many fluid flows of practical importance. A review of the different stages of vortex growth is given. In the linear regime, nonparallel effects completely govern this growth, and parallel flow theories do not capture the essential features of the development of the vortices. A detailed comparison between the parallel and nonparallel theories is given and it is shown that at small vortex wavelengths, the parallel flow theories have some validity; otherwise nonparallel effects are dominant. New results for the receptivity problem for Goertler vortices are given; in particular vortices induced by free stream perturbations impinging on the leading edge of the walls are considered. It is found that the most dangerous mode of this type can be isolated and it's neutral curve is determined. This curve agrees very closely with the available experimental data. A discussion of the different regimes of growth of nonlinear vortices is also given. Again it is shown that, unless the vortex wavelength is small, nonparallel effects are dominant. Some new results for nonlinear vortices of 0(1) wavelengths are given and compared to experimental observations.

138 citations


Journal ArticleDOI
TL;DR: In this article, an experimental investigation was conducted to examine the dynamic stall characteristics of a NACA 23012 aerofoil section at a Reynolds number of 1.5 million and the static stall mechanism was determined to be via abrupt upstream movement of trailing edge separation.
Abstract: An experimental investigation was conducted to examine the dynamic stall characteristics of a NACA 23012 aerofoil section at a Reynolds number of 1.5 million. Time-dependent data were obtained from thirty miniature pressure transducers and three hot film gauges situated at the mid-span of the wing. The static stall mechanism of the NACA 23012 was determined to be via abrupt upstream movement of trailing edge separation. Under dynamic conditions, stall was found to occur via leading edge separation, followed by a strong suction wave that moved across the aerofoil. This suction wave is characteristic of a strong moving vortex disturbance. Evidence of strong secondary vortex shedding was also found to occur, and this appears symptomatic of dynamic stall only at low Mach numbers. Some evidence of flow reversals over the trailing edge of the aerofoil were indicated prior to the development of leading edge separation and dynamic stall.

123 citations


Journal ArticleDOI
TL;DR: In this article, the response to the incident sound and the resulting flow instability were studied experimentally and therically on the basis of the linear stability theory, for a flat-plate airfoil, at a chord Reynolds number R c =4 x 10 4.
Abstract: To control the leading-edge flow separation on an airfoil by means of acoustic excitation, the response to the incident sound and the resulting flow instability are studied experimentally and therically on the basis of the linear stability theory, for a flat-plate airfoil, at a chord Reynolds number R c =4 x 10 4 .

100 citations


Proceedings ArticleDOI
TL;DR: In this article, the influence of high mainstream turbulence on leading edge film effectiveness and heat transfer coefficient was studied using a blunt body with a semicylinder leading edge with a flat afterbody.
Abstract: The influence of high mainstream turbulence on leading edge film effectiveness and heat transfer coefficient was studied. High mainstream turbulence was produced by a passive grid and a jet grid. Experiments were performed using a blunt body with a semicylinder leading edge with a flat afterbody. The mainstream Reynolds number based on leading edge diameter was about 100,000. Spanwise and streamwise distributions of film effectiveness and heat transfer coefficient in the leading edge and on the flat sidewall were obtained for three blowing ratios, through rows of holes located at ± 15 and ± 40 deg from stagnation

87 citations


Journal ArticleDOI
TL;DR: In this article, the effect of leading edge sweep on the vortex lift and leading-edge vortex strength of a slender wing was investigated, and the suction analogy was used in association with numerical and experimental data to derive simple formulas yielding the actual relationship.
Abstract: An effort is made to clarify the effect of leading-edge sweep on the vortex lift and leading-edge vortex strength of a slender wing; while it is often assumed that increasing sweep enhances vortex lift and strength, the opposite is the case. The suction analogy is used in association with numerical and experimental data to derive simple formulas yielding the actual relationship for delta wings. The difference between vortex lift and nonlinear lift is highlighted.

Patent
21 Aug 1990
TL;DR: In this paper, the authors propose to improve processing efficiency and to improve carrying performance by attaching one end part of a film to a leading member provided with plural locking holes and carrying the leading member in a state where the locking holes are locked with a rotating sprocket.
Abstract: PURPOSE: To improve processing efficiency and to improve carrying performance by attaching one end part of a film to a leading member provided with plural locking holes and carrying the leading member in a state where the locking holes are locked with a rotating sprocket. CONSTITUTION: The square locking holes 26 are formed at equal intervals along the longitudinal direction of a leader 25 near the center part of the leader 25 in a width direction, and the teeth of the sprocket 8 are inserted in the hole 26. Two films F are connected to the trailing edge of the leader 25 in parallel and inclined notched parts 28 are formed on both side ends of the leading edge part of the leader 25 in order to facilitate the passage of the leader 25. In such a case, the film F is not directly carried but it is hauled and carried by the leader 25 which is allowed to precede. Thus, processing efficiency is improved, the carrying performance of the film is improved, and the trouble of jamming is drastically decreased. COPYRIGHT: (C)1992,JPO&Japio

Patent
25 May 1990
TL;DR: In this article, an air bearing slider for supporting an electromagnetic transducer over a rotating disk is presented. The slider comprises a slider body having a leading edge, a trailing edge and first and second side edges.
Abstract: An air bearing slider for supporting an electromagnetic transducer over a rotating disk. The slider comprises a slider body having a leading edge, a trailing edge and first and second side edges. First and second side rails are positioned along the first and second side edges, respectively, and form air bearing surfaces with inside and outside edges. The inside and outside edges converge from the leading edge to a break and diverge from the break to the trailing edge.

Journal ArticleDOI
TL;DR: In this article, it is suggested that the observed instability of the shape of the leading edge is a result of the dynamics of the fluid in this bulge, and that the conditions at the edges can be satisfied, but only when the singularity associated with the moving contact line is removed.
Abstract: Experiments by Huppert (1982) have demonstrated that a finite volume of fluid placed on an inclined plane will elongate into a thin sheet of fluid as it slides down the plane. If the fluid is initially placed uniformly across the plane, the sheet retains its two-dimensionality for some time, but when it has become sufficiently long and thin, the leading edge develops a spanwise instability. A similarity solution for this motion was derived by Huppert, without taking account of the edge regions where surface tension is important. When these regions are examined, it is found that the conditions at the edges can be satisfied, but only when the singularity associated with the moving contact line is removed. When the sheet is sufficiently elongated, the profile of the free surface shows an upward bulge near the leading edge. It is suggested that the observed instability of the shape of the leading edge is a result of the dynamics of the fluid in this bulge. The related problem of a ridge of fluid sliding down the plane is examined and found to be linearly unstable. The spanwise lengthscale of this instability is, however, dependent on the width of the channel occupied by the fluid, which is at variance with the observed nature of the instability. Preliminary numerical solutions for the nonlinear development of a small disturbance to the position of a straight leading edge show the incipient development of a finger of fluid with a width that does not depend on the channel size, in accordance with the observations.

Proceedings ArticleDOI
01 Jan 1990
TL;DR: In this paper, a 75 deg sweep delta wing with a sharp leading edge is presented, and the sensitivity of the solution to the numerical scheme is examined using both a partially upwind scheme and a scheme with central differencing in all directions.
Abstract: Navier-Stokes solutions of subsonic vortical flow over a 75 deg sweep delta wing with a sharp leading edge are presented. The sensitivity of the solution to the numerical scheme is examined using both a partially upwind scheme and a scheme with central differencing in all directions. At moderate angles of attack, no vortex breakdown is observed, whereas the higher angle-of-attack cases exhibit breakdown. The effect of numerical grid density is investigated, and solutions that are obtained with various grid densities are compared with experimental data. An embedded grid approach is implemented to enable higher resolution in selected isolated flow regions, such as the leeward-side surface, the leading-edge vortical flow, and the vortex breakdown region.

Journal ArticleDOI
TL;DR: In this article, the authors used a stroboscopic schlieren system to study the effect of free-stream Mach number and reduced frequency on the dynamic stall vortex of a NACA 0012 airfoil.
Abstract: Compressibility effects on the dynamic stall of a NACA 0012 airfoil undergoing sinusoidal oscillatory motion were studied using a stroboscopic schlieren system. Schlieren pictures and some quantitative data derived from them are presented and show the influence of free-stream Mach number and reduced frequency on the dynamic-stall vortex. This study shows that a dynamic stall vortex always forms near the leading edge and convects on the airfoil upper surface at approximately 0.3 times the free stream velocity for all cases studied. The results also demonstrate that initiation of the dynamic stall vortex is delayed to higher angles of attack with increased reduced frequency, but that dynamic stall occurs at lower angles of incidence with increasing Mach numbers.

Patent
25 Sep 1990
TL;DR: In this article, a movable flaperon seal is attached at its leading edge to the leading edge of the main portion of the wing, and a connecting structure is provided to pivot the seal flap such that the opening between the main wing portion (20b) and leading edge (22a) on the upper surface is selectively closed by the movable flap at predetermined angular positions.
Abstract: The present invention provides an aircraft wing (10) having a main portion (20) with a trailing edge (20b) and a movable flaperon (22) hingedly secured at the trailing edge A movable flaperon seal (40) is hingedly attached at its leading edge to the trailing edge of the main portion of the wing Interconnecting structure is provided between the main portion of the wing and the flaperon seal Such structure is operable to pivot the seal flap such that the opening between the trailing edge of the main wing portion (20b) and the leading edge of said movable flap (22a) on the upper surface is selectively closed by the movable flap at predetermined angular positions of the movable flap

Book ChapterDOI
01 Jan 1990
Abstract: The dynamical behavior governing the propagation of evaporation waves in chlorinated fluorocarbons is studied in a constant-diameter vertical glass test cell which exhausts into a large, low-pressure reservoir. Care is taken to suppress heterogeneous nucleation within the liquid column. The test liquid is initially in equilibrium with its own vapor, sealed by a foil diaphragm. Upon diaphragm rupture, a series of expansion waves depressurizes the liquid to approximately the reservoir pressure, during which nucleation and subsequent rapid vaporization begin at the free surface. After an approximately 10 ms long start-up transient, a quasi-steady process develops during which the wavefront propagates into the stagnant liquid column at constant average velocity, generating a nonuniform high-speed two-phase flow. The leading edge of the wavefront consists of smooth and rough bubbles with maximum diameters of order 1 mm and characteristic lifetimes of order 1 ms. High speed movies show that the nucleation rate is both spatially nonuniform and temporally nonsteady, which leads to significant unsteadiness in the propagation of the wave. Fragmentation of the liquid into fine droplets occurs primarily as the result of the violent break-up of the leading-edge bubbles coincident with explosive bursts of aerosol, which occur in the region extending about 1 cm downstream of the leading edge bubble layer. These two processes appear to be mutually interactive. Three distinct modes of flow initiation are observed depending on the liquid superheat. Moreover, a self-initiation threshold is observed, below which waves do not occur. We observe that waves can propagate at slightly lower superheats if they are started artificially. However, an absolute threshold for wave propagation exists which is related to the nonsteady processes alluded to above.

Journal ArticleDOI
TL;DR: In this paper, the influence of the body nose radius and aerodynamic loading in the leading edge region of a free-stream flow has been analyzed for vortical and acoustic free stream disturbances.
Abstract: : Receptivity processes by which free-stream disturbances generate Tollmien-Schlichting waves in boundary layers have been analyzed using asymptotic methods for high Reynolds numbers. Vortical and acoustic free-stream disturbances have been considered. Receptivity occurs in the vicinity of the leading edge, and in localized regions further downstream where some feature (e. g., a wall hump) produces a short-scale disturbance to the mean flow. Nonlinear effects related to the free-stream pressure field have been found to play an important role in localized receptivity to vortical disturbances. For leading- edge receptivity, the influences of the body nose radius and aerodynamic loading in the leading-edge region have been analyzed. In the absence of aerodynamic loading, an increase in the body nose radius decreases the leading-edge receptivity coefficient. However, strong aerodynamic loading leads to a dramatic increase in the leading-edge receptivity coefficient, negating the decrease due to a larger nose radius. The propagation of an instability wave past a junction between a rigid wall and a surface with non-zero compliance or admittance has also been analyzed. The junction can cause energy to be scattered from the instability wave to higher eigenmodes, effectively attenuating the instability wave.

Journal ArticleDOI
TL;DR: In this paper, the so-called slender wing rock is caused by asymmetric vortex shedding from highly swept wing leading edges, and a completely different flow mechanism causes wing rock for aircraft with moderately swept leading edges.
Abstract: Limit cycle oscillations in roll of advanced aircraft can result from three different fluid mechanical flow processes The so-called slender wing rock is caused by asymmetric vortex shedding from highly swept wing leading edges A completely different flow mechanism causes wing rock for aircraft with moderately swept leading edges In this case, the causative mechanism is dynamic airfoil stall

Journal ArticleDOI
TL;DR: In this article, a Karman vortex street with an elliptical edge is investigated using flow visualization, and pressure fields induced by these interactions are measured by a phase-averaging technique and correlated with visualized flow patterns for basic classes of interactions.
Abstract: The interaction of a Karman vortex street with an elliptical edge is investigated experimentally. Basic types of interaction, as a function of scale and transverse displacement of the incident vortex street, are revealed using flow visualization. Unsteady pressure fields induced by these interactions are measured by a phase-averaging technique and correlated with the visualized flow patterns for basic classes of interactions.For a generic vortex–edge interaction, measurements of the phase-averaged velocity field allow construction of streamlines and vorticity contours showing the details of the interaction, including distortion of the vortical structures near the edge. The pressure field is calculated from the measured velocity field and interpreted in relation to the vortical structures.Simulation of flow visualization using the measured velocity field demonstrates possible misinterpretations related to the underlying vorticity field.

Journal ArticleDOI
TL;DR: In this paper, the authors describe the experimental observations of cavitation inception and noise from five model propellers, three basic and two modified, tested in the open jet test section of the Indian Institute of Science high-speed water tunnel facility.


Patent
27 Jul 1990
TL;DR: An elongated, flexible urethane member is bonded and firmly affixed to the leading edge of a glass fiber reinforced polyester skin fan blade for large diameter industrial water cooling tower fans.
Abstract: An elongated, flexible protective urethane member is bonded and firmly affixed to the leading edge of a glass fiber reinforced polyester skin fan blade for large diameter industrial water cooling tower fans. The polyester blade without such protective member would be subject to leading edge abrasion and deterioration during use. The flexible protective member is applied to the blade prior to curing of the chemically thickened polyester skin. Firm bonding and adherence of the protective member to the leading edge of the blade skin is obtained by curing of the skin with the protective member in place over the leading edge of the blade. Mechanical connection of the urethane member to the polyeste blade body is accomplished by provision of a series of holes along opposed longitudinal margins of the member which allow fluid polyester resin to flow into such openings during cure of the blade body resin layers, and by application of a glass fiber reinforced synthetic resin hold-down strip over opposed longitudinally extending edges of the hold-down strips and adjacent areas of the blade skin. Thus, upon completion of the cure cyle, the polyester resin within the openings cross-links with the underlying resin material and the overlying hold-down strips to more securely lock the member to the blade body.

Patent
11 May 1990
TL;DR: A double-layer medical catheter with an integral soft tip is made by coextrusion of a relatively rigid inner layer and a relatively soft outer layer, where the extrusion equipment is configured and so controlled to interrupt the supply of the material for the inner layer to form a periodic void in the inner wall as mentioned in this paper.
Abstract: A double-layer medical catheter with an integral soft tip is made by the coextrusion of a relatively rigid inner layer and a relatively soft outer layer, where the extrusion equipment is configured and so controlled to interrupt the supply of the material for the inner layer to form a periodic void in the inner wall. The act of interrupting the supply causes a ramp down in the inner wall thickness at the leading edge of each void and the ramp up of the thickness at the trailing edge. The void is cut to produce two ideal integral soft-tipped catheters.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the unsteady load and vibration behavior of vertical lift gates for different gate-bottom geometries and disharge conditions in an open channel and at a conduit inlet, and showed that the slope of the mean lift curve acting on the gate bottom provides an effective means of predicting with reasonable accuracy the critical range of gate openings with respect to potential gate vibration.
Abstract: The unsteady load and vibration behavior of vertical‐lift gates was investigated for different gate‐bottom geometries and disharge conditions in an open channel and at a conduit inlet. In all cases, vibrations occurred in specific ranges of a dimensionless velocity parameter whenever the flow fluctuated between complete separation and reattachment at the gate bottom. The excitation mechanism was attributed to the combined effect of shear‐layer instabilities and motion‐induced vortices shed at the leading edge of the gate bottom. Many puzzling features of in‐flow and cross‐flow vibration of gates with flow underneath can thus be clarified. In addition, it is shown that the slope of the mean lift curve acting on the gate bottom provides an effective means of predicting with reasonable accuracy the critical range of gate openings with respect to potential gate vibration. The prediction method is illustrated in a practical case.

Journal ArticleDOI
TL;DR: In this paper, a pitching delta wing is examined in a water channel for a range of mean angle of attack, and the wing is perturbed sinusoidally over a tenfold range of reduced frequency to determine the nature of the vortex development and breakdown.
Abstract: Flow past a pitching delta wing is examined in a water channel for a range of mean angle of attack. The wing is perturbed sinusoidally over a tenfold range of reduced frequency, in order to determine the nature of the vortex development and breakdown. There occur two basic types of vortex development: at low frequencies, the vortex core develops in the upstream direction towards the apex; at high frequencies, there is ejection of the leading edge of the vortex core from the apex in the downstream direction

Patent
26 Sep 1990
TL;DR: In this paper, a sync signal is constituted by a code train capable of deciding that the sync signal includes a code not existing in the conversion rule into a run-length-limited code during reproduction using a leading edge data or trailing edge data relative to the transition pattern.
Abstract: If information is to be recorded on and reproduced from a recording medium in correspondence between a code train in the form of a run-length-limited code and the positions of the leading edge and the trailing edge data of a status transition pattern such as pits, recording domains, a sync signal is inserted at regular intervals in the information converted in the form of the run-length-limited code The sync signal is constituted by a code train capable of deciding that the sync signal includes a code not existing in the conversion rule into a run-length-limited code during reproduction using a leading edge data or trailing edge data relative to the transition pattern

Patent
James A. Garman1
10 Sep 1990
TL;DR: In this paper, a cutting edge assembly is provided having a base edge with a scalloped leading edge and a plurality of teeth is provided and each tooth is releasably attached in space relation to the base edge.
Abstract: Cutting edge assemblies are normally utilized on the leading edge of implements to protect the leading edge of the implement from wear. In order to have a readily removable cutting edge assembly that can be replaced in the field, it is necessary to provide fastening means to retain the respective components to the implement. Since a surface and corresponding holes in the respective elements of the cutting edge assembly must be provided, the respective components are weakened and thus tend to break when used under high load conditions. In this subject arrangement, a cutting edge assembly is provided having a base edge with a scalloped leading edge. A plurality of teeth is provided and each tooth is releasably attached in space relation to the base edge. A plurality of base edge protectors is also provided and each protector is connected to the base edge between the respective teeth of the plurality of teeth. Furthermore, each tooth of the plurality of teeth has a bottom portion which extends rearwardly from a forward end portion and subtends from a top portion thereof between two holes located therein. The plurality of teeth and the plurality of base edge protectors provide a substantially continuous cutting edge for the implement while the bottom portion provides additional strength to the respective teeth.

Proceedings ArticleDOI
01 Jan 1990
TL;DR: In this article, an experimental investigation into the physical phenomena associated with limit cycle wing rock on slender delta wings has been conducted and the model used was a slender flat plate delta wing with 80-deg leading edge sweep.
Abstract: An experimental investigation into the physical phenomena associated with limit cycle wing rock on slender delta wings has been conducted. The model used was a slender flat plate delta wing with 80-deg leading edge sweep. The investigation concentrated on three main areas: motion characteristics obtained from time history plots, static and dynamic flow visualization of vortex position, and static and dynamic flow visualization of vortex breakdown. The flow visualization studies are correlated with model motion to determine the relationship between vortex position and vortex breakdown with the dynamic rolling moments. Dynamic roll moment coefficient curves reveal rate-dependent hysteresis, which drives the motion. Vortex position correlated with time and model motion show a time lag in the normal position of the upward moving wing vortex. This time lag may be the mechanism responsible for the hysteresis. Vortex breakdown is shown to have a damping effect on the motion.