Validated heat-transfer and pressure-drop prediction methods based on the discrete-element method: Phase 2, two-dimensional rib roughness

The paper describes experimental and numerical results of concrete fracture under quasi-static uniaxial compression. Experimental uniaxial compression tests were performed on concrete cubic specimens. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: three-dimensional X-ray microcomputed tomography, two-dimensional scanning electron microscope and manual two-dimensional digital microscope. The discrete element method was used to directly simulate experiments. Concrete was modelled as a random heterogeneous four-phase material composed of aggregate particles, cement matrix, interfacial transitional zones and macrovoids based on experimental images. Two- and three-dimensional analyses were carried out. In two-dimensional analyses, the real aggregate shape was created by means of clusters of spheres. In three-dimensional calculations, spheres were solely used. A satisfactory agreement between numerical and experimental results was achieved in two-dimensional analyses. The model was capable of accurately predicting complex crack paths and the corresponding stress–strain responses observed in experiments.

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Structural soil crust development from raindrop impacts using two-dimensional discrete element method

Computers & Geosciences ◽

10.1016/j.cageo.2016.09.004 ◽

2016 ◽

Vol 97 ◽

pp. 49-57 ◽

Cited By ~ 3

Author(s):

Seungcheol Yeom ◽

Kurt Sjoblom

Keyword(s):

Discrete Element Method ◽

Discrete Element ◽

Soil Crust ◽

Two Dimensional ◽

Element Method

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Flow Regime Map for Two Dimensional Spouted Bed and Comparison with Simulation by Discrete Element Method.

KAGAKU KOGAKU RONBUNSHU ◽

10.1252/kakoronbunshu.25.1037 ◽

1999 ◽

Vol 25 (6) ◽

pp. 1037-1039 ◽

Cited By ~ 5

Author(s):

TOSHIRO TSUJI ◽

TOMOKO CHIBA ◽

TOSHIHARU SHIBATA ◽

OSAMU UEMAKI ◽

HIRONORI ITOH

Keyword(s):

Discrete Element Method ◽

Flow Regime ◽

Discrete Element ◽

Two Dimensional ◽

Spouted Bed ◽

Regime Map ◽

Flow Regime Map ◽

Element Method

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Predicting Skin Friction and Heat Transfer for Turbulent Flow Over Real Gas-Turbine Surface Roughness Using the Discrete-Element Method

Volume 6: Turbo Expo 2003, Parts A and B ◽

10.1115/gt2003-38813 ◽

2003 ◽

Cited By ~ 4

Author(s):

Stephen T. McClain ◽

B. Keith Hodge ◽

Jeffrey P. Bons

Keyword(s):

Heat Transfer ◽

Surface Roughness ◽

Wind Tunnel ◽

Discrete Element Method ◽

Skin Friction ◽

Gas Turbine ◽

Discrete Element ◽

Real Gas ◽

Roughness Elements ◽

Element Method

The discrete-element method considers the total aerodynamic drag on a rough surface to be the sum of shear drag on the flat part of the surface and the form drag on the individual roughness elements. The total heat transfer from a rough surface is the sum of convection through the fluid on the flat part of the surface and the convection from each of the roughness elements. The discrete-element method has been widely used and validated for predicting heat transfer and skin friction for rough surfaces composed of sparse, ordered, and deterministic elements. Real gas-turbine surface roughness is different from surfaces with sparse, ordered, and deterministic roughness elements. Modifications made to the discrete-element roughness method to extend the validation to real gas-turbine surface roughness are detailed. Two rough surfaces found on high-hour gas-turbine blades were characterized using a Taylor-Hobson Form Talysurf Series 2 profilometer. Two rough surfaces and two elliptical-analog surfaces were generated for wind-tunnel testing using a three-dimensional printer. The printed surfaces were scaled to maintain similar boundary-layer thickness to roughness height ratio in the wind tunnel as found in gas-turbine operation. The results of the wind tunnel skin friction and Stanton number measurements and the discrete-element method predictions for each of the four surfaces are presented and discussed. The discrete-element predictions made considering the gas-turbine roughness modifications are within 7% of the experimentally-measured skin friction coefficients and are within 16% of the experimentally-measured Stanton numbers.

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