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1.
Summary The effects of superposing streamwise vorticity, periodic in the lateral direction, upon two-dimensional asymptotic suction flow are analyzed. Such vorticity, generated by prescribing a spanwise variation in the suction velocity, is known to play an important role in unstable and turbulent boundary layers. The flow induced by the variation has been obtained for a freestream velocity which (i) is steady, (ii) oscillates periodically in time, (iii) changes impulsively from rest. For the oscillatory case it is shown that a frequency can exist which maximizes the induced, unsteady wall shear stress for a given spanwise period. For steady flow the heat transfer to, or from a wall at constant temperature has also been computed.Nomenclature (x, y, z) spatial coordinates - (u, v, w) corresponding components of velocity - (, , ) corresponding components of vorticity - t time - stream function for v and w - v w mean wall suction velocity - nondimensional amplitude of variation in wall suction velocity - characteristic wavenumber for variation in direction of z - T temperature - P pressure - density - coefficient of kinematic viscosity - coefficient of thermal diffusivity - (/v w)2 - frequency of oscillation of freestream velocity - nondimensional amplitude of freestream oscillation - /v w 2 - z z - yv w y/ - v w 2 t/4 - /v w - U 0 characteristic freestream velocity - u/U 0 - coefficient of viscosity - w wall shear stress - Prandtl number (/) - q heat transfer to wall - T w wall temperature - T (T wT)/(T w–)  相似文献   

2.
In this paper, results from a combined network/averaging study are presented. The emphasis is placed on understanding the flow phenomena, rather than predicting results for real porous media. Idealized porous media, consisting of networks of tubes, are used to interpret two of the terms in the averaged momentum equation. In particular, it is demonstrated that the pressure term accounts for microscopic cross flow, and that the magnitude of this term is proportional to the variation of the cross-sectional areas of the tubes in the macroscopic flow direction. For one-dimensional macroscopic flow in these idealized porous media, the agreement of network theory and averaging theory permeabilities depends on areosity (a term related to the area open to flow in a direction) remaining constant in the macroscopic flow direction; it may vary in other directions.  相似文献   

3.
In this paper we continue previous studies of the closure problem for two-phase flow in homogeneous porous media, and we show how the closure problem can be transformed to a pair of Stokes-like boundary-value problems in terms of pressures that have units of length and velocities that have units of length squared. These are essentially geometrical boundary value problems that are used to calculate the four permeability tensors that appear in the volume averaged Stokes' equations. To determine the geometry associated with the closure problem, one needs to solve the physical problem; however, the closure problem can be solved using the same algorithm used to solve the physical problem, thus the entire procedure can be accomplished with a single numerical code.Nomenclature a a vector that maps V onto , m-1. - A a tensor that maps V onto . - A area of the - interface contained within the macroscopic region, m2. - A area of the -phase entrances and exits contained within the macroscopic region, m2. - A area of the - interface contained within the averaging volume, m2. - A area of the -phase entrances and exits contained within the averaging volume, m2. - Bo Bond number (= (=(–)g2/). - Ca capillary number (= v/). - g gravitational acceleration, m/s2. - H mean curvature, m-1. - I unit tensor. - permeability tensor for the -phase, m2. - viscous drag tensor that maps V onto V. - * dominant permeability tensor that maps onto v , m2. - * coupling permeability tensor that maps onto v , m2. - characteristic length scale for the -phase, m. - l characteristic length scale representing both and , m. - L characteristic length scale for volume averaged quantities, m. - n unit normal vector directed from the -phase toward the -phase. - n unit normal vector representing both n and n . - n unit normal vector representing both n and n . - P pressure in the -phase, N/m2. - p superficial average pressure in the -phase, N/m2. - p intrinsic average pressure in the -phase, N/m2. - p p , spatial deviation pressure for the -phase, N/m2. - r 0 radius of the averaging volume, m. - r position vector, m. - t time, s. - v fluid velocity in the -phase, m/s. - v superficial average velocity in the -phase, m/s. - v intrinsic average velocity in the -phase, m/s. - v v , spatial deviation velocity in the -phase, m/s. - V volume of the -phase contained within the averaging volmue, m3. - averaging volume, m3. Greek Symbols V /, volume fraction of the -phase. - viscosity of the -phase, Ns/m2. - density of the -phase, kg/m3. - surface tension, N/m. - (v +v T ), viscous stress tensor for the -phase, N/m2.  相似文献   

4.
Knowles' representation theorem for harmonically time-dependent free surface waves on a homogeneous, isotropic elastic half-space is extended to include harmonically time-dependent free processes for thermoelastic surface waves in generalized thermoelasticity of Lord and Shulman and of Green and Lindsay.r , , r , , .This work was done when author was unemployed.  相似文献   

5.
In this paper we present an asymptotic analysis of the three-dimensional problem for a thin linearly elastic cantilever =×(0,l) with rectangular cross-section of sides and 2, as goes to zero. Under suitable assumptions on the given loads, we show that the three-dimensional problem converges in a variational sense to the classical one-dimensional model for extension, flexure and torsion of thin-walled beams. Mathematics Subject Classifications (2000) 474K20, 74B10, 49J45.  相似文献   

6.
We consider singularly perturbed systems , such that=f(, o, 0). o m , has a heteroclinic orbitu(t). We construct a bifurcation functionG(, ) such that the singular system has a heteroclinic orbit if and only ifG(, )=0 has a solution=(). We also apply this result to recover some theorems that have been proved using different approaches.  相似文献   

7.
8.
We prove results on the asymptotic behavior of solutions to discrete-velocity models of the Boltzmann equation in the one-dimensional slab 0x<1 with=" general=" stochastic=" boundary=" conditions=" at=" x="0" and=" x="1." assuming=" that=" there=" is=" a=" constant=">wall Maxwellian M=(M i) compatible with the boundary conditions, and under a technical assumption meaning strong thermalization at the boundaries, we prove three types of results:
I.  If no velocity has x-component 0, there are real-valued functions 1(t) and 2(t) such that in a measure-theoretic sense f i(0, t) 1 (t)M i , f i(1, t) 2 (t)M i as t. 1 and 2 are closely related and satisfy functional equations which suggest that 1(t)1 and 2(t)1 as t.
II.  Under the additional assumption that there is at least one non-trivial collision term containing a product f k f l with k = l , where k denotes the x-component of the velocity associated with f k , we show that in a measure-theoretic sense 1(t) and 2(t) converge to 1 as t. This entails L 1-convergence of the solution to the unique wall Maxwellian. For this result, k = l =0 is admissible.
III.  In the absence of any collision terms, but under the assumption that there is an irrational quotient ( i +¦ j ¦)/( l +¦ k ¦) (here i , l >0 and j , k <0), renewal=" theory=" entails=" that=" the=" solution=" converges=" to=" the=" unique=" wall=" maxwellian=" in=">L .
Communicated by L. Arkeryd  相似文献   

9.
A stochastic model for flow through inhomogeneous fractured reservoirs of double porosity, based on Barenblattet al.'s continuum approach, is presented. The fractured formation is conceptualized as an interconnected fracture network surrounding porous blocks, and amenable to the continuum approach. The block permeability is negligible in comparison to that of the fractures, and therefore the reservoir permeability is represented by the permeability of the fracture network. The fractured reservoir inhomogeneity is attributed to the fracture network, while the blocks are considered homogeneous. The mathematical model is represented by a coupled system of partial differential random equations, and a general solution for the average and for the correlation moments of the fracture pressure are obtained by the Neumann expansion (or Adomian decomposition). The solution for pressure is represented by an infinite series and an approximate solution for radial flow, is obtained by retaining the first two terms of the series. The purpose of this investigation is to get an insight on the pressure behavior in inhomogeneous fractured reservoirs and not to obtain type curves for determination of reservoir properties, which owing to the nonuniqueness of the solution, is impossible. For the present analysis we assumed an ideal reservoir with cylindrical symmetric inhomogeneity around the well. Fractured rock reservoirs being practically inhomogeneous, it is of interest to compare the pressure behavior of such reservoirs, with Warren and Roots's solution for (ideal) homogeneous reservoirs, used as a routine for determining the fractured reservoir characteristic parameters and, using the results of well tests. The comparison of the results show that inhomogeneous and homogeneous reservoirs exhibit a similar pressure behavior. While the behavior is identical, the same drawdown or a build-up pressure curve may be fitted by different characteristic dimensionless parameters and, when attributed to an inhomogeneous or a homogeneous reservoir. It is concluded that the ambiguity in determining the fractured reservoir and, makes questionable the usefulness of determination of these parameters. Computations were also carried out to determine the correlation between the fracture pressure at the well and the fracture pressure at different points.  相似文献   

10.
Zusammenfassung Ein Vergleich im Frequenzbereich zeigt, daß bei der Berechnung der Verweilzeitverteilung mit dem Dispersionsmodell das endlich begrenzte System für Péclet-Zahlen Pe > 10 mit guter Näherung durch ein einseitig unbegrenztes System und für Pe > 50 durch ein beidseitig unbegrenztes System ersetzt werden kann.
The dispersion model. A comparison of approximations
A comparison in the frequency domain shows that for the determination of the residence time distribution with the dispersion model the finitely restricted system may be substituted with good approximation for Peclet numbers Pe > 10 by a one-side unrestricted system and for Pe > 50 by a both-side unrestricted system.

Bezeichnungen A Rohrquerschnitt - A=A mittlerer Strömungsquerschnitt in der Schüttschicht - Konzentration (Partialdichte) der Bezugskomponente i - Bezugskonzentration nach Gl. (5) - ci Konzentration (Dichte) der reinen Bezugskomponente i - D axialer Dispersionskoeffizient - E Fehler im Frequenzbereich nach Gl. (36) - G(,) Übertragungsfunktion - G(,i) Frequenzgang - L Länge der Schüttschicht - m Masse - Massenstrom - Péclet-Zahl - s Laplace-Variable - t Zeit - t Impulsbreite - v Strömungsgeschwindigkeit im leeren Rohr - mittlere axiale Strömungsgeschwin digkeit in der Schüttschicht - V=AL Zwischenraumvolumen der Schüttschicht - x Ortskoordinate - (t) Dirac-Stoss - Porosität - dimensionslose Zeit - dimensionslose Konzentration - Laplace-Transformierte der Konzentration - Fourier-Transformierte der Konzentration - dimensionslose Ortskoordinate - =s dimensionslose Laplace-Variable - mittlere Verweilzeit - Kreisfrequenz - = dimensionslose Kreisfrequenz Indices A Ausgang - D Dispersion - E Eingang - i Bezugskomponente - K Konvektion Mitteilung Nr. 44 des Institutes für Mess-und Regel-technik der Eidgenössischen Technischen Hochschule Zürich (Vorsteher: Prof. Dr. P. Profos)  相似文献   

11.
In this paper the flow is studied of an incompressible viscous fluid through a helically coiled annulus, the torsion of its centre line taken into account. It has been shown that the torsion affects the secondary flow and contributes to the azimuthal component of velocity around the centre line. The symmetry of the secondary flow streamlines in the absence of torsion, is destroyed in its presence. Some stream lines penetrate from the upper half to the lower half, and if is further increased, a complete circulation around the centre line is obtained at low values of for all Reynolds numbers for which the analysis of this paper is valid, being the ratio of the torsion of the centre line to its curvature.Nomenclature A =constant - a outer radius of the annulus - b unit binormal vector to C - C helical centre line of the pipe - D rL - g 1000 - K Dean number=Re2 - L 1+r sin - M (L 2+ 2 r 2)1/2 - n unit normal vector to C - P, P pressure and nondimensional pressure - p 0, p pressures of O(1) and O() - Re Reynolds number=aW 0/ - (r, , s), (r, , s) coordinates and nondimensional coordinates - nonorthogonal unit vectors along the coordinate directions - r 0 radius of the projection of C - t unit tangent vector to C - V r, V , V s velocity components along the nonorthogonal directions - Vr, V, V s nondimensional velocity components along - W 0 average velocity in a straight annulus Greek symbols , curvature and nondimensional curvature of C - U, V, W lowest order terms for small in the velocity components along the orthogonal directions t - r, , s first approximations to V r , V, V s for small - =/=/ - kinematic viscosity - density of the fluid - , torsion and nondimensional torsion of C - , stream function and nondimensional stream function - nondimensional streamfunction for U, V - a inner radius of the annulus After this paper was accepted for publication, a paper entitled On the low-Reynolds number flow in a helical pipe, by C.Y. Wang, has appeared in J. Fluid. Mech., Vol 108, 1981, pp. 185–194. The results in Wangs paper are particular cases of this paper for =0, and are also contained in [9].  相似文献   

12.
We consider a surface S = (), where 2 is a bounded, connected, open set with a smooth boundary and : 3 is a smooth map; let () denote the components of the two-dimensional linearized strain tensor of S and let 0 with length 0 > 0. We assume the the norm ,|| ()||0, in the space V0() = { H1() × H1() × L2(); = 0 on 0 } is equivalent to the usual product norm on this space. We then establish that this assumption implies that the surface S is uniformly elliptic and that we necessarily have 0 = .  相似文献   

13.
Two thermodynamical models of pseudoelastic behaviour of shape memory alloys have been formulated. The first corresponds to the ideal reversible case. The second takes into account the hysteresis loop characteristic of this shape memory alloys.Two totally independent techniques are used during a loading-unloading tensile test to determine the whole set of model parameters, namely resistivity and infrared thermography measurements. In the ideal case, there is no difficulty in identifying parameters.Infrared thermography measurements are well adapted for observing the phase transformation thermal effects.Notations 1 austenite 2 martensite - () Macroscopic infinitesimal strain tensor of phase - (2) f Traceless strain tensor associated with the formation of martensite phase - Macroscopic infiniesimal strain tensor - Macroscopic infinitesimal strain tensor deviator - f Trace - Equivalent strain - pe Macroscopic pseudoelastic strain tensor - x Distortion due to parent (austenite =1)product (martensite =2) phase transformation (traceless symmetric second order tensor) - M Total mass of a system - M() Total mass of phase - V Total volume of a system - V() Total volume of phase - z=M(2)/M Weight fraction of martensite - 1-z=M(1)/M Weight fraction of austenite - u 0 * () Specific internal energy of phase (=1,2) - s 0 * () Specific internal entropy of phase - Specific configurational energy - Specific configurational entropy - 0 f (T) Driving force for temperature-induced martensitic transformation at stress free state ( 0 f T) = T *Ts *) - Kirchhoff stress tensor - Kirchhoff stress tensor deviator - Equivalent stress - Cauchy stress tensor - Mass density - K Bulk moduli (K 0=K) - L Elastic moduli tensor (order 4) - E Young modulus - Energetic shear (0 = ) - Poisson coefficient - M s o (M F o ) Martensite start (finish) temperature at stress free state - A s o (A F o ) Austenite start (finish) temperature at stress free state - C v Specific heat at constant volume - k Conductivity - Pseudoelastic strain obtained in tensile test after complete phase transformation (AM) (unidimensional test) - 0 Thermal expansion tensor - r Resistivity - 1MPa 106 N/m 2 - () Specific free energy of phase - n Specific free energy at non equilibrium (R model) - n eq Specific free energy at equilibrium (R model) - n v Volumic part of eq - Specific free energy at non equilibrium (R L model) - conf Specific coherency energy (R L model) - c Specific free energy at constrained equilibria (R L model) - it (T) Coherency term (R L model)  相似文献   

14.
New asymptotic approaches for dynamical systems containing a power nonlinear term x n are proposed and analyzed. Two natural limiting cases are studied: n 1 + , 1 and n . In the firstcase, the 'small method' (SM)is used and its applicability for dynamical problems with the nonlinearterm sin as well as the usefulness of the SMfor the problem with small denominators are outlined. For n , a new asymptotic approach is proposed(conditionally we call it the 'large method' –LM). Error estimations lead to the followingconclusion: the LM may be used, even for smalln, whereas the SM has a narrow application area. Both of the discussed approaches overlap all values ofthe parameter n.  相似文献   

15.
Tests conducted on a model Busemann biplane catamaran in a towing basin qualitatively showed that the form of the wave drag coefficient curve followed the typical drag curve for a single unswept supersonic wing, but on this was superimposed that of the Busemann wave drag curve (giving a local minimum near the design Froude number).  相似文献   

16.
The Stokes flow of two immiscible fluids through a rigid porous medium is analyzed using the method of volume averaging. The volume-averaged momentum equations, in terms of averaged quantities and spatial deviations, are identical in form to that obtained for single phase flow; however, the solution of the closure problem gives rise to additional terms not found in the traditional treatment of two-phase flow. Qualitative arguments suggest that the nontraditional terms may be important when / is of order one, and order of magnitude analysis indicates that they may be significant in terms of the motion of a fluid at very low volume fractions. The theory contains features that could give rise to hysteresis effects, but in the present form it is restricted to static contact line phenomena.Roman Letters (, = , , and ) A interfacial area of the- interface contained within the macroscopic system, m2 - A e area of entrances and exits for the -phase contained within the macroscopic system, m2 - A interfacial area of the- interface contained within the averaging volume, m2 - A * interfacial area of the- interface contained within a unit cell, m2 - A e * area of entrances and exits for the-phase contained within a unit cell, m2 - g gravity vector, m2/s - H mean curvature of the- interface, m–1 - H area average of the mean curvature, m–1 - HH , deviation of the mean curvature, m–1 - I unit tensor - K Darcy's law permeability tensor, m2 - K permeability tensor for the-phase, m2 - K viscous drag tensor for the-phase equation of motion - K viscous drag tensor for the-phase equation of motion - L characteristic length scale for volume averaged quantities, m - characteristic length scale for the-phase, m - n unit normal vector pointing from the-phase toward the-phase (n = –n ) - p c p P , capillary pressure, N/m2 - p pressure in the-phase, N/m2 - p intrinsic phase average pressure for the-phase, N/m2 - p p , spatial deviation of the pressure in the-phase, N/m2 - r 0 radius of the averaging volume, m - t time, s - v velocity vector for the-phase, m/s - v phase average velocity vector for the-phase, m/s - v intrinsic phase average velocity vector for the-phase, m/s - v v , spatial deviation of the velocity vector for the-phase, m/s - V averaging volume, m3 - V volume of the-phase contained within the averaging volume, m3 Greek Letters V /V, volume fraction of the-phase - mass density of the-phase, kg/m3 - viscosity of the-phase, Nt/m2 - surface tension of the- interface, N/m - viscous stress tensor for the-phase, N/m2 - / kinematic viscosity, m2/s  相似文献   

17.
Zusammenfassung Mit Hilfe der Mischungswegtheorie wurden Gleichungen zur Berechnung der Geschwindigkeitsprofile und des Druckabfalles bei der turbulenten, abwärtsterichteten Gas/Film-Strömung aufgestellt. Zur Berechnung des Wärmeübergangs wurde die turbulente Temperaturleitfähigkeit aus einem halbempirischen Ansatz bestimmt. Es konnte eine befriedigende Übereinstimmung zwischen den berechneten und gemessenen Nußelt-Zahlen bei der Oberflächenverdampfung erzielt werden. Zur Auslegung von Fallstromverdampfern wurde ein Computerprogramm erstellt. Damit lassen sich Einflußgrößen wie Wandtemperatur, Filmdicke, Verdampfungsrate usw. in Abhängigkeit von der Lauflänge bestimmen.
Flow and heat transfer in surface evaporation and film condensation
Using the mixing length model, equations were established to calculate the velocity profiles and pressure drop in turbulent downward directed gas/film flow. The thermal diffusivity needed for the calculation of heat transfer was determined from a semiempirical model. The calculated Nußelt-numbers agreed very well with experiments. For the design of falling-film evaporators, a computer program was developed, which enables to evaluate wall temperature, film thickness, evaporation rate etc. as a function of flow-path length.

Formelzeichen a Temperaturleitfähigkeit - c spez. Wärmekapazität - d Durchmesser - fm bezogene mittlere turbulente Temperaturleitfähigkeit - Fi /(32/g)1/3) Filmkennzahl - Fr Froude-Zahl - g Fallbeschleunigung - Ka 3/g4 Kapitza-Zahl - L Rohrlänge - l Mischungsweg - m Massenstrom - Nu (2/g)1/3/ Nußelt-Zahl - Nu / Nußelt-Zahl des Filmes - p Druck - Pr /a Prandtl-Zahl - q Wärmestromdichte - R Radius - Re Reynolds-Zahl - Reü Übergangs-Reynolds-Zahl - Rew Schubspannungs-Reynolds-Zahl der Flüssigkeit - r radiale Koordinate - T Temperatur - u Geschwindigkeit - uw Schubspannungsgeschwindigkeit der Flüssigkeit - u Grenzflächengeschwindigkeit - uT Schubspannungsgeschwindigkeit des Gases - y Wandabstand - y* y/ dimensionsloser Wandabstand - z axiale Koordinate Griechische Zeichen Wärmeübergangskoeffizient - Filmdicke - dyn. Viskosität - dimensionslose Temperatur - Wärmeleitfähigkeit - kin. Viskosität - Dichte - Oberflächenspannung - Schubspannung Zusatzzeichen und Indizes G Gas - K Kondensation - s Sättigung - t turbulent - w Wand - wi Welleninstabilität - Phasengrenze - - mittlere Größe  相似文献   

18.
Heat transfer enhancement in viscous liquid flows by means of twisted-tape inserts has been investigated in this study. Internal flows in horizontal tubes with uniform wall temperature have been considered. This is representative of typical conditions encountered in practical applications in the chemical and process industry. Experimental data were obtained for water and ehtylene glycol with snug-fit tape inserts of three different twist ratios,y=3.0, 4.5, and 6.0; the tape thickness in each case was 0.483 mm. The data cover a wide range of flow parameters: 3.5Pr<100, and=">Re<35,000, for=" both=" heating=" and=" cooling=" conditions.=" the=" results=">Nu m andf are strongly influenced by the tape geometry and fluid flow conditions, and can be functionally represented byNu m=(Re, Pr, b/w,L/d, H/d, /d) andf=(Re, H/d, /d).In dieser Untersuchung wurde die Verbesserung des Wärmeübergangs in viskosen Flüssigkeitsströmungen mittels eines Spiralband-Einsatzes erforscht. Es wurden Strömungen in horizontalen Rohren mit einheitlicher Wandtemperatur betrachtet. Diese sind repräsentativ für typische Bedingungen, die in praktischen Anwendungen in der chemischen und weiterverarbeitenden Industrie anzutreffen sind. Für Wasser und Äthylen-Glykol wurden experimentelle Daten für eingepaßte Band-Einsätze mit drei unterschiedlichen Verdrehungsverhältnisseny=3.0, 4.5 und 6.0 erhalten; die Breite des Bandes betrug jeweils 0.483 mm. Die Daten decken einen weiten Bereich von Strömungsparametern ab: 3.5Pr<100 und=">Re<35,000 für=" die=" beiden=" betriebsbedingungen=" heizen=" und=" kühlen.=" die=" ergebnisse=">Nu m undf sind stark abhängig von der Bandgeometrie und den Strömungsbedingungen und können zweckmäßig durchNu m=(Re, Pr, b/w,L/d, H/d, /d) undf=(Re, H/d, /d) dargestellt werden.Dedicated to Prof. Dr.-Ing. U. Grigull's 80th birthday  相似文献   

19.
In this paper we develop the averaged form of the Stokes equations in terms of weighting functions. The analysis clearly indicates at what point one must choose a media-specific weighting function in order to achieve spatially smoothed transport equations. The form of the weighting function that produces the cellular average is derived, and some important geometrical theorems are presented.Roman Letters A interfacial area of the- interface associated with the local closure problem, m2 - A e area of entrances and exits for the-phase contained within the averaging system, m2 - A p surface area of a particle, m2 - d p 6V p/Ap, effective particle diameter, m - g gravity vector, m/s2 - I unit tensor - K m permeability tensor for the weighted average form of Darcy's law, m2 - L general characteristic length for volume averaged quantities, m - L p general characteristic length for volume averaged pressure, m - L characteristic length for the porosity, m - L v characteristic length for the volume averaged velocity, m - l characteristic length (pore scale) for the-phase - l i i=1, 2, 3 lattice vectors, m - (y) weighting function - m(–y) (y), convolution product weighting function - v special weighting function associated with the traditional averaging volume - m v special convolution product weighting function associated with the traditional averaging volume - m g general convolution product weighting function - m V unit cell convolution product weighting function - m C special convolution product weighting function for ordered media which produces the cellular average - m D special convolution product weighting function for disordered media - m M master convolution product weighting function for ordered and disordered media - n unit normal vector pointing from the-phase toward the-phase - p pressure in the-phase, N/m2 - pm superficial weighted average pressure, N/m2 - p m intrinsic weighted average pressure, N/m2 - p traditional intrinsic volume averaged pressure, N/m2 - p p p m , spatial deviation pressure, N/m2 - r 0 radius of a spherical averaging volume, m - r m support of the convolution product weighting function, m - r position vector, m - r position vector locating points in the-phase, m - V averaging volume, m3 - V volume of the-phase contained in the averaging volume, m3 - V cell volume of a unit cell, m3 - V velocity vector in the-phase, m/s - vm superficial weighted average velocity, m/s - v m intrinsic weighted average velocity, m/s - V volume of the-phase contained in the averaging volume, m3 - V p volume of a particle, m3 - v traditional superficial volume averaged velocity, m/s - v v p m spatial deviation velocity, m/s - x position vector locating the centroid of the averaging volume or the convolution product weighting function, m - y position vector relative to the centroid, m - y position vector locating points in the-phase relative to the centroid, m Greek Letters indicator function for the-phase - Dirac distribution associated with the- interface - V /V, volume average porosity - m m * . weighted average porosity - mass density of the-phase, kg/m3 - viscosity of the-phase, Ns/m2 - V /V, volume fraction of the-phase  相似文献   

20.
Let u, p be a weak solution of the stationary Navier-Stokes equations in a bounded domain N, 5N . If u, p satisfy the additional conditions
  相似文献   

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