47 research outputs found
Hugo Forchheimer, Frankfurt A/M., Eytelweinstrasse 9 (Osthafen), Dampfsägewerke-Import-Holzgrosshandlung, Stromlänge Passau, Detail-Lager Frankfurt a/M., Eytelweinstrasse Osthafen Zentral-Bureau Frankfurt a. Main, New Orleans, La, U.S.A., Filialen: New York, N-Y, Pensacola. Fla., Beaumont, Tex
No full textHUGO FORCHHEIMER, FRANKFURT A/M., EYTELWEINSTRASSE 9 (OSTHAFEN), DAMPFSÄGEWERKE-IMPORT-HOLZGROSSHANDLUNG, STROMLÄNGE PASSAU, DETAIL-LAGER FRANKFURT A/M., EYTELWEINSTRASSE OSTHAFEN ZENTRAL-BUREAU FRANKFURT A. MAIN, NEW ORLEANS, LA, U.S.A., FILIALEN: NEW YORK, N-Y, PENSACOLA. FLA., BEAUMONT, TEX
Hugo Forchheimer, Frankfurt A/M., Eytelweinstrasse 9 (Osthafen), Dampfsägewerke-Import-Holzgrosshandlung, Stromlänge Passau, Detail-Lager Frankfurt a/M., Eytelweinstrasse Osthafen Zentral-Bureau Frankfurt a. Main, New Orleans, La, U.S.A., Filialen: New York, N-Y, Pensacola. Fla., Beaumont, Tex ( -
MHD Darcy-Forchheimer Slip Flow in a Porous Medium with Variable Thermo-Physical Properties
No full textAbstract: MHD Darcy-Forchheimer Slip Flow in a Porous Medium with Variable Thermo-Physical Properties was studied. The governing partial differential equations are converted into nonlinear ordinary differential equations using a similarity transformation and solved numerically. The variable and thermal conductivity were studied. Different physical parameters’ effects on temperature, velocity and concentration distribution are studied. The effects of Darcy-Forchheimer parameter, suction/blowing parameter, velocity slip and thermal slip parameter on the velocity, temperature and mass transfer rates nature are examined with the aid of graphs. Schmidt number and Soret number effect are also presented. The results shows that when the porosity parameter is increased, the velocity of the fluid decrease, while temperature profile and skin friction decreases. Also increasing the velocity slip parameter result in increase in velocity and Nusselt number whereas the concentration decreases in same case. Also the temperature at a point decreases with increase in thermal slip parameter while the skin friction decrease in both cases.
Keywords: Darcy-Forchheimer, Porous medium, Slip flow, Magneto-hydrodynamics (MHD), variable viscosity, thermal conductivity.
Title: MHD Darcy-Forchheimer Slip Flow in a Porous Medium with Variable Thermo-Physical Properties
Author: A.L. Panya, O. A. Akinyemi, A.M. Okedoye
International Journal of Mechanical and Industrial Technology
ISSN 2348-7593 (Online)
Vol. 10, Issue 2, October 2022 - March 2023
Page No: 30-43
Research Publish Journals
Website: www.researchpublish.com
Published Date: 16-February-2023
DOI: https://doi.org/10.5281/zenodo.7646344
Paper Download Link (Source)
https://www.researchpublish.com/papers/mhd-darcy-forchheimer-slip-flow-in-a-porous-medium-with-variable-thermo-physical-propertiesInternational Journal of Mechanical and Industrial Technology, ISSN 2348-7593 (Online), Research Publish Journals, Website: www.researchpublish.co
Forchheimer & ancient hydraulic works in Turkey
No full textForchheimer has dealt with the remains of ancient water supply systems of Istanbul and Ephesus during his stay in Turkey in the periods of 1889-1891 and 1914-1918. His findings were published in 1890 in the "Zeitschrift des Vereins Deutscher Ingenieure", in 1893 as a book in Vienna with J. Strzygowski as co-author, and in 1923 as part of book of the Austrian Archeological Institute
Permeability and Turbulence Over Perforated Plates
No full textWe perform direct numerical simulations of turbulent flow at friction Reynolds number Reτ≈ 500 - 2000 grazing over perforates plates with moderate viscous-scaled orifice diameter d+≈ 40 - 160 and analyse the relation between permeability and added drag. Unlike previous studies of turbulent flows over permeable surfaces, we find that the flow inside the orifices is dominated by inertial effects, and that the relevant permeability is the Forchheimer and not the Darcy one. We find evidence of a fully rough regime where the relevant length scale is the inverse of the Forchheimer coefficient, which can be regarded as the resistance experienced by the wall-normal flow. Moreover, we show that, for low porosities, the Forchheimer coefficient can be estimated with good accuracy using a simple analytical relation.In this article the author name Stefan Hickel was incorrectly written as Hickel Stefan. The original article has been corrected.Aerodynamic
Numerical analysis of the Forchheimer coefficients and the maximum pressures for a dike with impermeable core and permeable Elastocoast layer
No full textThe Van der Meer formula for amour stability takes the Iribarren number, number of waves and damage level into account. It also contains a factor P which describes the “notional permeability” of the breakwater. This factor is based on the fact that a more permeable structure dissipates more energy and hence requires less heavy armouring. Its value depends on the different layer designs of the breakwater. The notional permeability (P) was empirically determined by van der Meer [1988] for three different standard situations, to be exact the P=0,1, P=0,5 and P= 0,6. It is difficult to find the exact value of this parameter. From a physical point of view the value of P should depend on the Forchheimer coefficients. These coefficients describe the permeability of the filter layers and core of the structure. Without these coefficients a breakwater cannot be accurately calculated in a numerical model. The intention of this research is to use the IH-2VOF model and to determine the pressures by the transition zone from the core of the breakwater with impermeable core and permeable layer. In the Großer Wellen Kanal (GWK) in Germany tests were done for a dike with impermeable core and permeable Elastocoast layer with a porosity of 0,388 and a stone diameter of 34mm. The maximum pressure which is measured in the GWK is 5,6 kPa. In this study the results of these GWK tests are compared with the mathematical model. This test is simulated in the IH2-VOF model with non impact regular waves with Hm = 0,18m, Tm = 5,93 sec and a water depth of 3,40 m. For this study 190 combinations of Forchheimer coefficients are run with the VOF model. The Forchheimer coefficient ? is varied between 200 and 2000 and the coefficient ? is varied between 1,0 and 1,9. Finally, twelve possible combinations of the coefficients gave an error less than one percent and two of these combinations gave the smallest error of 0,3 percent. This combinations are ? = 200 and ? = 1,7 and ? = 1700 and ? = 1,7. By the impact regular wave test with Hm = 0,98m and Tm = 2,99 with the same Forchheimer coefficient as above, the model gave an error of approximately 45% in the prediction of the pressures. In the next step of this research it is tried to improve the value of the Forchheimer coefficient by using a constant value ? = 1700 and ? = 1,7 and change the stone diameter and the porosity to find a better agreement with the maximum pressure. The porosity is varied between 0,25 and 0,55 and the stone diameter is varied between 8,5 mm to 136 mm. The results of the tests are close to each other. Only the tests with a porosity of 0,25 and stone diameter of 8,5 mm are not near to the real value of 10,77 kPa. The porosity and the stone diameter have an impact on the maximum pressure. However, after a certain value, the impact is noticeable. Hence it is possible to choose by a porosity of 0,388 a stone diameter between 0,017 m and 0,136 m and by a diameter of 0,034 m a porosity between 0,35 and 0,45. These values have not a big impact on the maximum pressure. The dike is also tested with Irregular waves with number of waves of 400 and the wave height Hm = 0,8 m. Different tests are run with the model for different Iribarren numbers which is varied between 1,0 to 5,0. It is visible that the Iribarren number and the maximum pressure are related to each other for both plunging and surging waves. In contrast to what has been mentioned above, the maximum pressure and the filter velocity for surging waves gave quite irregular results, whereas by plunging waves there is a regularity with the filter velocity and maximum pressure. The main conclusion of this research is that when using a VOF model to predict pressures inside a breakwater, it is essential to have a correct value of the Forchheimer coefficients. Simply using a standard value on the basis of the grain size only is not accurate enough.Hydraulic EngineeringHydraulic EngineeringCivil Engineering and Geoscience
MATHEMATICAL FRAMEWORK OF THE WELL PRODUCTIVITY INDEX FOR FAST FORCHHEIMER (NON-DARCY) FLOWS IN POROUS MEDIA
No full textMotivated by the reservoir engineering concept of the well Productivity Index, we introduced and analyzed a functional, denoted as "diffusive capacity", for the solution of the initial-boundary value problem (IBVP) for a linear parabolic equation.21 This IBVP described laminar (linear) Darcy flow in porous media; the considered boundary conditions corresponded to different regimes of the well production. The diffusive capacities were then computed as steady state invariants of the solutions to the corresponding time-dependent boundary value problem. Here similar features for fast or turbulent nonlinear flows subjected to the Forchheimer equations are analyzed. It is shown that under some hydrodynamic and thermodynamic constraints, there exists a so-called pseudo steady state regime for the Forchheimer flows in porous media. In other words, under some assumptions there exists a steady state invariant over a certain class of solutions to the transient IBVP modeling the Forchheimer flow for slightly compressible fluid. This invariant is the diffusive capacity, which serves as the mathematical representation of the so-called well Productivity Index. The obtained results enable computation of the well Productivity Index by resolving a single steady state boundary value problem for a second-order quasilinear elliptic equation. Analytical and numerical studies highlight some new relations for the well Productivity Index in linear and nonlinear cases. The obtained analytical formulas can be potentially used for the numerical well block model as an analog of Piecemann. © 2009 World Scientific Publishing Company.The research of the first author was partially supported by the NSF Grant DMS-0813825 and by the ARP Grant 0212-44-C399. The research of the fourth author was supported by Award No. KUS-C1-016-04, made by King Abdullah University of Science and Technology (KAUST)
Acoustic liners and their induced drag
No full textIn order to reduce the noise emitted by aircraft engines, the nacelle is coated with acoustic liners. An undesirable effect of these surfaces is that they increase the aerodynamic drag. In the present work, we characterize this type of surface roughness by performing Direct Numerical Simulations of fully resolved acoustic liner geometries. We find evidence of a fully rough regime, whose onset is determined by the value of the viscous-scaled Forchheimer coefficient. Moreover, the intensity of the wall-normal velocity fluctuations at the wall also scales with the viscous-scaled wall-normal permeability, leading to a relation between fluctuations and added drag.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Aerodynamic
Elementenmethode in niet-lineaire grondwaterstroming
No full textOpzetten van een numerieke oplossing van grondwaterstroming (met de Forchheimer vergelijkingen) in poreuze media (grond, breuksteen).Hydraulic EngineeringCivil Engineering and Geoscience
Formulating the behavior of thermal radiation and magnetic dipole effects on Darcy–Forchheimer grasped ferrofluid flow
No full textIn this article a boundary layer analysis has been carried out to examine the Darcy–Forchheimer flow of Carreau ferrofluid through a sensor duct between two parallel plates. The top plate is assumed to be squeezed whereas the lower plate is at rest. Inspection has been accomplished in the occupancy of thermal radiation and magnetic dipole. Thermal conductivity is also considered, which is determined by temperature. After incorporating these speculations, dimensional equations supervising the flow and heat transfer distinctions are transfigured into a dimensionless system of differential equations by implementing similarity transformations. The result of squeezed flow index b, ferrohydrodynamic interaction β∗, porous medium permeability parameter S1, local inertia coefficient S2, Eckert number λ, Prandtl number Pr, Curie temperature g, and Weissenberg number We on velocity and temperature curves are observed. The numerical solution for boundary layer momentum and energy equations is obtained. The present analysis demonstrates that velocity profile significantly drops owing to a rise in Weissenberg number.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Experimental assessment of the flow resistance of coastal wooden fences
No full textWooden fences are applied as a nature-based solution to support mangrove restoration along mangrove coasts in general and the Mekong Delta coast in particular. The simple structure uses vertical bamboo poles as a frame to store horizontal bamboo and tree branches (brushwood). Fence resistance is quantitatively determined by the drag coefficient exerted by the fence material on the flow; however, the behaviour of drag is predictable only when the arrangement of the cylinders is homogeneous. Therefore, for more arbitrary arrangements, the Darcy-Forchheimer equations need to be considered. In this study, the law of fluid flow was applied by forcing a constant flow of water through the fence material and measuring the loss of hydraulic pressure over a fence thickness. Fences, mainly using bamboo sticks, were installed with model-scale and full-scale diameters applying two main arrangements, inhomogeneous and staggered. Our empirical findings led to several conclusions. The bulk drag coefficient (CD) is influenced by the flow regime represented by Reynolds number. The drag coefficient decreases with the increase of the porosity, which strongly depends on fence arrangements. Finally, the Forchheimer coefficients can be linked to the drag coefficient through a related porosity parameter at high turbulent conditions. The staggered arrangement is well-predicted by the Ergun-relations for the Darcy-Forchheimer coefficients when an inhomogeneous arrangement with equal porosity and diameter leads to a large drag and flow resistance.Coastal EngineeringHydraulic Structures and Flood Ris
