Boundary shear in rectangular and compound ducts by Harish S. Patel Download PDF EPUB FB2
Boundary Shear in Smooth Boundary shear in rectangular and compound ducts book Ducts and mean boundary shear stresses on the duct walls in terms of the aspect ratio. Recommended. Cited By. Cited By Recommended Boundary Shear in Symmetrical Compound Channels.
Journal of Boundary shear in rectangular and compound ducts book Engineering October Cited by: Experiments have been performed in a rectangular duct for aspect ratios, B/H, varying between and in a compound duct comprising of one rectangular main channel and two symmetrically disposed flood plains, for (H-h)/HB/b = and b/h =in order to obtain boundary shear stress distributions and primary flow isovels.
follows page Mean flow distributions of primary velocity and boundary shear stress were measured in a wide closed duct with a range of asymmetric compound cross-sections. The cross-sectional geometries included three different wall angles, vertical, and (vertical:horizontal) at the interface between the shallow and deep by: The measured data of boundary shear in square ducts are used to quantify some empirical coefficients.
The model is then applied to the corner region of rectangular ducts and open channels. With those simplifications and approximations applied to the streamwise vorticity equation, the predictions are found to. Velocity and boundary shear in a wide compound duct Article in Journal of Hydraulic Research September (5) January with 15 Reads How we measure 'reads'.
Results of laboratory experiments on wide smooth rectangular ducts are reported in terms of the relationship between duct aspect ratio b / h and the shear force on the walls expressed as a proportion of the total boundary shear force, % SF data set, in the range ≤ b / h ≤ 50, overlaps and extends the work of Knight and Patel, for which ≤ b / h ≤ Experimental results are presented concerning the boundary shear stress distribution in a rectangular compound section channel comprising rectangular main channel and two symmetrically disposed ﬂoodplains.
Di erent dimensionless ratios of shear stress distributions are obtained and related to relevant parameters. wall shear stress in rectangular channels, prismatic channels and ducts. More contributions by Patra and Kar , Khatua and Patra , Khatua et al.
 towards the boundary shear stress distribution in meandering as well as straight compound channels having smooth surface is worthy to discuss. The primary shear wall element of a compound shear wall was designed considering an effective flange width of 12”, which becomes the minimum boundary zone length that extends into the web of the secondary shear wall element (Figure 2).
This analysis ensured a primary shear wall boundary zone length based on the l w to l w for P. In this paper, we considered the laminar fully developed flow, of a Newtonian fluid, in ducts of rectangular cross-section.
Poisson’s partial differential equation Saint-Venant solution was used, to calculate Poiseuille number values whatever is rectangles aspect ratio. From these results, we considered limit cases of square duct and plane Poiseuille flow (infinite parallel plates).
The fully developed velocity profile for rectangular ducts has been determined, using an analogy with the stress function of the theory of elasticity (Timoshenko and Goodier ) by Dryden et al. , and Marco and Han .Consider the cross section of a rectangular duct, characterized by its aspect ratio α* = 2b/2a, as shown in Fig.
36 with the flow direction along the x axis. For the heat transfer problem, they considered the (H 1) thermal boundary condition for doubly connected ducts.
Cheng and Jamil also presented graphically shear stress distribution, fluid temperature gradients at the wall, and fluid velocity and temperature profiles for typical duct geometries.
Figure 1 Rectangular cross-section considered in fluid mechanics. Theory of laminar flow in rectangular ducts Considering cartesian coordinates(xyz,)with origin at the centre of the duct of rectangular cross-section, the fully established laminar flow of a Newtonian liquid is described by the following well-known Poisson equation: 22 22 zz vv.
Table 1 shows the experimental conditions and width-averaged velocity, U w, for trapezoidal channel tests in Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6; and Table 2 indicates the same conditions for rectangular channel tests in Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. All trapezoidal flow tests utilised the sidewall slope parameter of s = 1 (the physical meaning of s can be found at Fig.
Experimental results are presented concerning the boundary shear stress and boundary shear force distributions in a compound section comprising of one rectangular main channel and two symmetrically disposed flood plains. The results of some laboratory experiments are reported concerning the distribution of boundary shear stresses in smooth closed ducts of a rectangular cross section for aspect ratios between 1 and Shear stress is calculated from the Prandtl-Von Karman Universal Velocity Distribution Law.
The laboratory experimental investigation reveals that shear stress increases with the increase of depth and width ratio and low magnitude of boundary shear is observed in the outer bend as compare to the inner bend in a compound meandering channel.
Yang S-Q and Lim S-Y Boundary shear stress distribution in smooth rectangular open channel flows, Proc. Inst. Civil Eng. Water Maritime and Energy (9) Crossref Google Scholar Yang S-Q and McCorquodale J A Determination of boundary shear stress and Reynolds shear stress in smooth rectangular channel flows, J.
Hydraul. This paper deals with the manner in which a shear layer proximate to the wall of an acoustically treated rectangular duct modifies the attenuation spectra. The restriction of this shear layer to the region near the lined duct walls is aimed at simulating boundary layer effects on the attenuation.
The first of these is the boundary layer, or region near a solid boundary where viscous effects have reduced the velocity below the free-stream value.
The reduced velocity in the boundary layer implies, as mentioned in Chapter 2, a decrease in the capacity of a channel or duct to carry flow and one effect of the boundary layer is that it acts. 2. Boundary Shear Water flowing in an open channel is restricted by resistance from the bed and side slopes of the channel.
This force of resistance conveys the boundary shear force. Boundary shear stress is the tangential component of the. A detailed experimental study of developing turbulent flow in a rectangular duct was made using a laser-Doppler anemometer.
The purposes of the work were to obtain data of value to fluid mechanicists, particularly those interested in the development and testing of mathematical turbulence models, and to evaluate the performance of the anemometer.
formed by the free surface, the bottom boundary, and two pairs of imaginary planes normal to the bottom and with unit spacing, one pair parallel to the flow and spaced a distance B apart, and the other normal to the flow and spaced a distance L apart (Figure ). Figure Definition sketch for deriving the boundary shear stress in.
Boundary-layer separation in the low-momentum corner flow regions is observed to occur upstream of the center-flow field by approximately one duct height. The leading edge shock train structure is composed of a hybrid oblique–normal shock front, with oblique shocks spawning from the corner flow separation transforming into a normal shock.
Donald W. Knight's 95 research works with 3, citations and 6, reads, including: The lateral distribution of depth-averaged velocity in a channel flow bend. The obtained equation for rectangular channels could estimate values closer to experimental data, but the equations for ducts had poor, inaccurate results in predicting wall and bed shear stress.
The turbulent flow in a compound meandering channel with a rectangular cross section is one of the most complicated turbulent flows, because the flow behaviour is influenced by several kinds of force. PDF | On Mar 1,Shu-Qing Yang published Discussion of “Semianalytical Model for Shear Stress Distribution in Simple and Compound Open Channels” by A.
Zarrati, Y. Jin, and S. test ducts. For his test duct regarding complex boundary as Fig. 2, the flow characteristics could be analyzed by dividing the duct into two simple rectangular ducts as upper and lower parts.
Experimental data by Tracy in were only reported velocity measurements in lower part, hence, measurements in the compound channel only the. Figure A uniform open-channel flow: the depth and the velocity profile is the same at all sections along the flow.
12 One kind of problem that is associated with uniform flow is what the channel slope will be if discharge Q, water depth d, and bed sediment size D are specified or imposed upon the flow. The importance of the determination of boundary shear distribution and the applicability of measurement by surface pitot tube technique after Preston1in open channel flow are discussed.
The results of the investigation made to explore boundary shear distribution in a smooth and an artificially roughened compound channel are presented.
The distribution of shear is found to be non-uniform in. Prediction of boundary shear force distributions in open channel flow is crucial in many critical engineering problems such as channel design, calculation of losses and sedimentation.
During floods, part of the discharge of a river is carried by the simple main channel and the rest is carried by the floodplains. For such compound channels, the flow structure becomes complicated due to the. Rectangular ducts are widely used in heat transfer devices, for instance, in compact heat exchangers, gas turbine cooling systems, cooling channels in combustion chambers and nuclear reactors.
Forced turbulent heat convection in a square or rectangular duct is one of the fundamental problems in the thermal science and fluid mechanics.