NUMERICAL MODELING OF TSUNAMI INUNDATION OVER A COASTAL CITY USING SUB-GRID SCALE DRAG FORCE MODEL

The importance of accurate numerical modeling of tsunami inundation in an urban area has clearly realized due to the devastating damage from 2011 Tohoku Earthquake Tsunami. Although, numerical inundation simulations using high resolution topography data (O(1m)), the medium resolution tsunami inundation model (O(10m)-O(100m)) needs and useful for tsunami hazard assessment. This study develops and validates a numerical model of tsunami inundation using upscaled urban roughness parameterization: Drag Force Model (DFM) which deals with the effect of structures as drag force acting on flow based on physical modeling. The validation of the DFM reveals that the DFM can express the effect of the flow direction and inundation ratio.

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A new centrifugal correction drag force model for gas solid-particle two-phase flow

Powder Technology ◽

10.1016/j.powtec.2016.09.043 ◽

2016 ◽

Vol 303 ◽

pp. 124-129 ◽

Cited By ~ 3

Author(s):

Zhi Shang

Keyword(s):

Solid Particle ◽

Drag Force ◽

Two Phase Flow ◽

Force Model ◽

Phase Flow ◽

Two Phase

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Evaluation of the Performance of the Drag Force Model in Predicting Droplet Evaporation for R134a Single Droplet and Spray Characteristics for R134a Flashing Spray

Energies ◽

10.3390/en12244618 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4618

Author(s):

Zhi-Fu Zhou ◽

Dong-Qing Zhu ◽

Guan-Yu Lu ◽

Bin Chen ◽

Wei-Tao Wu ◽

...

Keyword(s):

Drag Force ◽

Droplet Diameter ◽

Radial Distance ◽

Droplet Evaporation ◽

Nozzle Diameter ◽

Force Model ◽

Straight Tube ◽

Single Droplet ◽

Spray Characteristics ◽

Two Phase

Drag force plays an important role in determining the momentum, heat and mass transfer of droplets in a flashing spray. This paper conducts a comparative study to examine the performance of drag force models in predicting the evolution of droplet evaporation for R134a single droplet and spray characteristics for its flashing spray. The study starts from single moving R134a droplet vaporizing in atomispheric environment, to a fully turbulent, flashing spray caused by an accidental release of high-pressure R134a liquid in the form of a straight-tube nozzle, using in-house developed code and a modified sprayFoam solver in OpenFOAM, respectively. The effect of the nozzle diameter on the spray characteristics of R134a two-phase flashing spray is also examined. The results indicate that most of the drag force models have little effect on droplet evporation in both single isolated droplet modelling and fully two-phase flashing spray simulation. However, the Khan–Richardson model contributes to different results. In particular, it predicts a much different profile of the droplet diameter distribution and a much lower droplet temperature in the radial distance. The nozzle diameter has a significant impact on the flashing spray. A smaller diameter nozzle leads to more internse explosive atomization, shorter penetration distance, lower droplet diameter and velocity, and a faster temperature decrease.

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A Method to Double the Extension Ability of Radial Jet Drilling Technology

Journal of Energy Resources Technology ◽

10.1115/1.4039977 ◽

2018 ◽

Vol 140 (9) ◽

Cited By ~ 6

Author(s):

Li Jingbin ◽

Zhang Guangqing ◽

Li Gensheng ◽

Huang Zhongwei ◽

Li Weichang

Keyword(s):

Drag Force ◽

Average Velocity ◽

Oil And Gas ◽

Damage Zone ◽

Force Model ◽

Gas Recovery ◽

Drainage Radius ◽

Velocity Flow ◽

Critical Issues ◽

Drilling Technology

Radial jet drilling (RJD) technology is an effective method to enhance oil and gas recovery by penetrating the near-wellbore damage zone, and increasing the drainage radius greatly. Recently, it is identified as a potential technology to develop the geothermal energy. But the extension ability, one of the most critical issues of the RJD, is limited. Because only high pressure flexible hose (HPFH), which is hard to be fed in and subjected to greater resistance by the diverter, can be used as the drill stem to turn from vertical to horizontal in the casing. In this paper, an innovative method to feed in the HPFH by the drag force generated by high velocity flow in narrow annulus is proposed. The drag force model is built, validated, and modified by theoretical and experimental ways. Results show that the resulting drag force, which is equivalent to the self-propelled force, can easily achieve and feed in the HPFH. There is a power law relationship between the drag force and the average velocity; the drag force increases linearly with the length of the narrow annulus. Higher average velocity and 1–1.5 m annulus length are recommended. According to force analysis, the extension ability of the RJD can be doubled theoretically by this method. The results of this paper will greatly promote the development of RJD technology.

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Modeling and Parameter Identification of an In-Tank Swimming Robot Performing Floor Inspection

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4041506 ◽

2018 ◽

Vol 141 (3) ◽

Cited By ~ 1

Author(s):

Imen Hbiri ◽

Houssem Karkri ◽

Fathi H. Ghorbel ◽

Slim Choura

Keyword(s):

Dynamic Model ◽

Drag Force ◽

Equations Of Motion ◽

Experimental Tests ◽

Force Model ◽

Friction Drag ◽

Control Laws ◽

Low Speed ◽

Advanced Control ◽

Computational Fluid Dynamics Cfd

In this paper, we develop the equations of motion at low-speed of a swimming robot for tank floor inspection. The proposed dynamic model incorporates a new friction drag force model for low-speed streamlined swimming robots. Based on a boundary layer theory analysis, we prove that for low-speed maneuvering case (Re from 103 to 105), the friction drag force component is nonlinear and is not insignificant, as previously considered. The proposed drag viscous model is derived based on hydrodynamic laws, validated via computational fluid dynamics (CFD) simulations, and then experimental tests. The model hydrodynamic coefficients are estimated through CFD tools. The robot wheels friction LuGre model is experimentally identified. Extensive experimental tests were conducted on the swimming robot in a circular water pool to validate the complete dynamic model. The dynamic model developed in this paper may be useful to design model-based advanced control laws required for accurate maneuverability of floor inspection swimming robots.

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New Interfacial Drag Force Model Including Effect of Bubble Wake, (I) Model Development for Steam-Water Bubbly Flow in Large-Diameter Pipes

Journal of Nuclear Science and Technology ◽

10.1080/18811248.1998.9733962 ◽

1998 ◽

Vol 35 (12) ◽

pp. 895-904 ◽

Cited By ~ 5

Author(s):

Tomio OKAWA ◽

Kimitoshi YONEDA ◽

Yuzuru YOSHIOKA

Keyword(s):

Drag Force ◽

Bubbly Flow ◽

Large Diameter ◽

Model Development ◽

Force Model ◽

Large Diameter Pipes ◽

Interfacial Drag

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A new drag force model for the wake acceleration effect and its application to simulation of bubbly flow

Progress in Nuclear Energy ◽

10.1016/j.pnucene.2014.11.015 ◽

2015 ◽

Vol 80 ◽

pp. 24-36 ◽

Cited By ~ 1

Author(s):

Xiang Chai ◽

Ivan Otic ◽

Xu Cheng

Keyword(s):

Drag Force ◽

Bubbly Flow ◽

Force Model

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Effect of microstructural anisotropy on the fluid–particle drag force and the stability of the uniformly fluidized state

Journal of Fluid Mechanics ◽

10.1017/jfm.2012.425 ◽

2012 ◽

Vol 713 ◽

pp. 27-49 ◽

Cited By ~ 6

Author(s):

William Holloway ◽

Jin Sun ◽

Sankaran Sundaresan

Keyword(s):

Friction Coefficient ◽

Drag Force ◽

Fluid Model ◽

Stokes Number ◽

Spherical Particles ◽

Force Model ◽

Drag Model ◽

Fluidized State ◽

Two Fluid Model ◽

Two Fluid

AbstractLattice-Boltzmann simulations of fluid flow through sheared assemblies of monodisperse spherical particles have been performed. The friction coefficient tensor extracted from these simulations is found to become progressively more anisotropic with increasing Péclet number, $Pe= \dot {\gamma } {d}^{2} / D$, where $\dot {\gamma } $ is the shear rate, $d$ is the particle diameter, and $D$ is the particle self-diffusivity. A model is presented for the anisotropic friction coefficient, and the model constants are related to changes in the particle microstructure. Linear stability analysis of the two-fluid model equations including the anisotropic drag force model developed in the present study reveals that the uniformly fluidized state of low Reynolds number suspensions is most unstable to mixed mode disturbances that take the form of vertically travelling waves having both vertical and transverse structures. As the Stokes number increases, the transverse-to-vertical wavenumber ratio decreases towards zero; i.e. the transverse structure becomes progressively less prominent. Fully nonlinear two-fluid model simulations of moderate to high Stokes number suspensions reveal that the anisotropic drag model leads to coarser gas–particle flow structures than the isotropic drag model.

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