Numerical studies on sloshing in rectangular tanks using a tree-based adaptive solver and experimental validation

Micro- and nanofabrication technology enables the application of electrokinetics as a method of performing chemical analyses and achieving liquid pumping in electronically-controlled microchip systems with no moving parts. We are studying and leveraging the unique separation modalities offered by nanoscale electrokinetic channels. We report analytical, numerical, and experimental investigations of nanochannel electrophoretic transport and separation dynamics of neutral and charged analytes. Our study includes continuum-theory-based analytical and numerical studies of nanofluidic electrophoretic separation dynamics, as well as experimental validation of these models. We have used 40, 100, and 1,560 nm deep channels etched in fused silica to independently measure mobility and valence of small ions. We also use these devices to separate 10 to 100 base pair DNA in the absence of a gel separation matrix. The effective free-solution mobilities of the ds-DNA oligonucleotides measured in 1560 nm deep channel are consistent with reported literature values, while smaller values of the mobility were measured for 4o nm deep channels for the same charge-species. The goal of our work is to explore and exploit electrokinetic flow regimes with extreme scales of length and charge density.

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Assessment of virtual thermal manikins for thermal comfort numerical studies. Verification and validation

E3S Web of Conferences ◽

10.1051/e3sconf/201911102018 ◽

2019 ◽

Vol 111 ◽

pp. 02018

Author(s):

Cristiana Croitoru ◽

Ilinca Nastase ◽

Florin Bode ◽

Gabriel Cojocaru

Keyword(s):

Turbulence Intensity ◽

Distribution Systems ◽

Experimental Validation ◽

Realistic Model ◽

Temperature Fields ◽

Air Distribution ◽

Cfd Simulations ◽

Thermal Discomfort ◽

Numerical Studies ◽

Velocity Turbulence

This study is a part of a larger experimental and numerical campaign intended to evaluate the influence of the turbulence intensity at the inlet of the terminal air distribution systems on the local draft sensation and thermal discomfort of ventilation users. In this paper we present preliminary results of CFD simulations using a realistic model of human body along with an experimental validation. The model is further used in a piston distribution scheme to evaluate the influence of turbulence intensity on the comfort indicators. The recorded velocity, turbulence and temperature fields allowed us to estimate the distributions of DR, PPD and PMV indexes. For the investigated case, the results indicated a direct correlation.

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Structural damping enhancement using a novel approach—a forward look

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406001522840 ◽

2000 ◽

Vol 214 (1) ◽

pp. 103-112 ◽

Cited By ~ 1

Author(s):

G. R. Tomlinson

Keyword(s):

Experimental Validation ◽

First Century ◽

Structural Damping ◽

Frequency Bandwidth ◽

Free Layer ◽

Cell Geometry ◽

Numerical Studies ◽

Novel Approach ◽

Damping Material ◽

Modes Of Vibration

This paper considers two aspects for enhancing structural damping using passive, but novel, methods. Attempting to take a forward look to the twenty-first century, the concept of using biological and evolutionary methods to ‘grow’ damping material on the surface of a vibrating component is described. A simple cantilever beam is used as the component and a ‘free-layer’ viscoelastic damping treatment is ‘grown’ on the structure in such a way as to provide optimum damping over a frequency bandwidth that encompasses flexural and torsional modes of vibration. To enhance the ‘controllability’ of the damping, the viscoelastic material is considered as a cellular material displaying a negative Poisson's ratio and it is shown that for the ‘free-layer’ treatment it is possible to produce a range of modal loss factors by changing the cell geometry. Only numerical studies are used and no experimental validation has been carried out, the idea being to stimulate ideas for future structural damping concepts.

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Numerical Studies of Vibration of Four-Span Continuous Plate with Rails Excited by Moving Car with Experimental Validation

International Journal of Structural Stability and Dynamics ◽

10.1142/s021945541750119x ◽

2017 ◽

Vol 17 (10) ◽

pp. 1750119 ◽

Cited By ~ 6

Author(s):

Jing Yang ◽

Huajiang Ouyang ◽

Dan Stancioiu

Keyword(s):

Experimental Validation ◽

Shell Element ◽

Modal Testing ◽

System Model ◽

Fe Model ◽

Shell Elements ◽

Beam Elements ◽

Young’S Moduli ◽

Numerical Studies ◽

Continuous Plate

The vibration of a four-span continuous plate with two rails on top and four extra elastic supports excited by a moving model car is studied through numerical simulations and experiments. Modal testing is carried out to identify the Young’s moduli of the plate material and the rail material. Shell elements and beam elements are adopted for the plate and the rails of their Finite Element (FE) model, respectively. An offset is required to connect the rails and the plate in the FE model and the offset ratio of the shell element is updated to bring the numerical frequencies of the structure (plate with rails) closest to its experimental frequencies. Modal Superposition (MS) method with numerical modes of the structure and an iterative method are combined to predict the vibration of the structure subjected to the moving car. The displacements of four points of the plate are measured during the crossing of the car and compared with predicted results. The two sets of results agree well, which validates the model of the system. Parametric analysis is then made using the validated system model.

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Hemodynamics Challenges for the Navigation of Medical Microbots for the Treatment of CVDs

Materials ◽

10.3390/ma14237402 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7402

Author(s):

Erica Doutel ◽

Francisco J. Galindo-Rosales ◽

Laura Campo-Deaño

Keyword(s):

Experimental Validation ◽

Dynamic Performance ◽

Circulatory System ◽

Physiological Conditions ◽

Hemodynamic Variables ◽

Numerical Studies ◽

Flow Disturbances ◽

Heart Cycle ◽

Human Circulatory System

Microbots have been considered powerful tools in minimally invasive medicine. In the last few years, the topic has been highly studied by researchers across the globe to further develop the capabilities of microbots in medicine. One of many applications of these devices is performing surgical procedures inside the human circulatory system. It is expected that these microdevices traveling along the microvascular system can remove clots, deliver drugs, or even look for specific cells or regions to diagnose and treat. Although many studies have been published about this subject, the experimental influence of microbot morphology in hemodynamics of specific sites of the human circulatory system is yet to be explored. There are numerical studies already considering some of human physiological conditions, however, experimental validation is vital and demands further investigations. The roles of specific hemodynamic variables, the non-Newtonian behavior of blood and its particulate nature at small scales, the flow disturbances caused by the heart cycle, and the anatomy of certain arteries (i.e., bifurcations and tortuosity of vessels of some regions) in the determination of the dynamic performance of microbots are of paramount importance. This paper presents a critical analysis of the state-of-the-art literature related to pulsatile blood flow around microbots.

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