Local Departure Research Articles

Some comments on steady, laminar flow through twisted pipes

Steady laminar flow through pipes of straight centre line and fixed cross-sectional geometry is consideredfor pipes in which the orientation of the cross-section changes slowly with distance along the axis of the pipe. For small rates of twist, the (local) departure from (local) Poiseuille flow is small and it is shown that a part of the mathematical problem for this secondary flow is identical to that for the small, transverse displacement of a clamped elastic plate due to constant loading. A detailed examination of the loss of flow rate (due to the twist) is given. The special case of a pipe of elliptical cross-section is found to be analytically tractable (with the aid of a computer) and is considered in detail.

Water-vapor Transfer by Forced-convection from a Leaf-shaped Plane Surface with Temperature-distribution

Fundamental analyses and some experiments regarding to water-vapor transfer by foced convection over a wetted leaf-shaped plane surface were made.In general, for a leaf-shaped plate, local water-vapor transfer coefficient (Dx) which is a function of wind velocity (u) and distance (x) over the surface from the leading edge in the direction of air-flow is written as follows:Dx=Bum2x-n2, where, B is a numerical coefficient affected by the shape of the plate, its relative position to wind, natures of air-flow and the boundary-layer, the vapor-concentration distribution over the surface, properties of air and so on; m1 and n1 are exponents related to the structure of the boundary-layer, respectively.Water-vapor concentration departure (ΔCx) of the surface from the air outside the boundary-layer is generally expressed as follows;ΔCx=Co+bu-m2xn2, where, b is a numerical coefficient and Co is a constant. When the temperature of the leading edge of the plate is identical to the air temperature, Co is the saturation deficit of air in vapor-concentration.A local evaporation-rate is obtained as the product of the local values of vapor transfer coefficient and vapor-concentration departure.Then, the relationships between a local and the average values of transfer coefficient, concentration departure and evaporation-rate were theoretically analysed and the effect of the surface-temperature distribution in the air-flow direction upon the convection vapor transfer coefficients was experimentally examined.I. For the plane-surface with the above described transfer coefficient and the distribution of vapor-concentration departure, each correction factor for obtaining the average value of transfer coefficient, concentration departure or evaporation-rate from each local value was calculated. These results are shown in figures (Figs. 1, 2-A and 3). For example, the correction factor of vapor transfer coefficient at the point where the distance from the leading edge in the air-flow direction is 40% of the surface dimension are 1.26 and 1.04 for laminar and turbulent boundary-layer, respectively.Further, the positions where a local value coincided with the average value for each quantity were derived. The distance of the position where a local vapor-concentration departure agrees with its average is about 40% of the surface dimension from the leading edge in the flow direction.The position for evaporation-rate is complicated as it is related to air-temperature, humidity, wind velocity, surface dimension and temperature departure of the surface from air. However, under moderate air conditions local evaporation-rates at positions whose distance from the leading edge being between about 26 and 30% of the surface-dimension in the flow direction agrees with the average rate for a flat leaf.II. Three representations of average evaporation-rate were shown in the cases of using (i) both local values of transfer coefficient and vapor-concentration departure, (ii) the average transfer coefficient and a local concentration departure, (iii) both average values of transfer coefficient and concentration departure.

Tectonics of the Mendocino Triple Junction

Interpretation of reflection profiles and of the magnetic anomaly pattern over the Gorda Basin and Escarpment gives broad agreement with the triple junction model of McKenzie and Morgan (1969). However, the basin has undergone internal deformation, a local departure from rigid plate tectonics, and the escarpment has had a component of underthrusting by the Gorda block. Faults in the Gorda Basin which disturb young turbidites parallel the trends of magnetic anomalies, suggesting deformation of the oceanic crust along lines of primary weakness. The northeast trends of the faults give a constraint on first-motion solutions for earthquakes within the basin and suggest left-lateral slip on the faults. Analysis of the geometry and timing of the Gorda Basin deformation based on the magnetic pattern gives an average gross tectonic strain rate of 10 −14 /sec. These observations give a measure of the mechanics of deformation of oceanic lithosphere very close to a spreading rise crest.

Studies of Extragalactic Nebulae. I. The Rotation Curve of NGC 4736

view Abstract Citations (48) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Studies of Extragalactic Nebulae. I. The Rotation Curve of NGC 4736 Chincarini, Guido ; Walker, Merle F. Abstract Spectrograms of NGC 4736 in position angles 33 , 107 , and 123 have been measured and the rotation curve of the galaxy determined out to a distance of about 50" from the center A previous study of this object indicated that a smooth rotation curve does not exist, which suggested the presence of non-circular motions. The present study shows that the rotation curve is smooth; only a small, local departure from circular motion in or near one set of spiral arms is observed. The mass has been determined by different methods and out to different radii. The mass-to (blue)4ight ratio has been determined and is found to be near 1, rather than of the order of 10 as is commonly assumed for Sb galaxies Publication: The Astrophysical Journal Pub Date: February 1967 DOI: 10.1086/149024 Bibcode: 1967ApJ...147..407C full text sources ADS | data products SIMBAD (1) NED (1) Related Materials (4) Part 2: 1967ApJ...147..416W Part 3: 1967ApJ...149..481W Part 4: 1967ApJ...149..487C Part 5: 1968ApJ...151...71W

The Effects of Winds on Water Levels on the New England Coast1

Tidal records from Nantucket Sound, Cape Cod; Montauk, Long Island; and Portland, Maine, have been studied along with wind and barometric observations from each location. Results of this study show that departures from mean sea level due to wind may be resolved into two components. The first is a component which refers to symmetrical sinusoidal variation of sea level departure as a function of wind direction and applies to the outer coast and to the general level of Nantucket Sound in particular.The second is an asymmetrical component which refers the responses of sea level at each observing station to local wind force, direction, fetch length, and local topography. Under different circumstances these components vary in relative importance in determining the local departure from mean sea level. In addition to wind direction and velocity, duration and size of wind field may determine whether one component is more important than the other.The varying importance of each component probably governs the time‐lag between peak winds and maximum sea level departures which will vary from several hours to as much as twenty hours.

Estimation in semiparametric time series regression

In this paper, we consider a semiparametric time series regression model and establish a set of identification conditions such that the model under discussion is both identifiable and estimable. We estimate the parameters in the model by using the method of moment and the nonlinear function by using the local linear method, and establish the asymptotic distributions for the proposed estimators. We then discuss how to estimate a sequence of local departure functions nonparametrically when the null hypothesis is rejected and establish some related asymptotic theory. Both the simulation study and the empirical application are also provided to illustrate the finite sample behavior of the proposed models and methods.