Recent attempts to discover energy–efficient and cost–effective power generation systems unleash tremendous capabilities of urban rooftops vertical–axis wind turbines (VAWT). Their advantages Omni–directionality, low noise less maintenance cost allow direct integration neighborhood having unstable conditions. Despite continuous effort investigate performance under a range operating conditions, aspects such as Turbulent Intensity (TI) ground clearance remain relatively explored. Such effects...

Purpose This study aims to simulate the dendritic growth in Stokes flow by iteratively coupling a domain and boundary type meshless method. Design/methodology/approach A preconditioned phase-field model for solidification of pure supercooled melt is solved strong-form space-time adaptive approach based on dynamic quadtree decomposition. The domain-type space discretisation relies monomial augmented polyharmonic splines interpolation. forward Euler scheme used time evolution. boundary-type...

Abstract Stable liquid jets are crucial for successful serial crystallography experiments. They produced from gas dynamic virtual nozzles (GDVNs), where the an inner capillary is focused by a co-flowing outer converging capillary. Our previously investigated non-Newtonian with incompressible and compressible focusing under atmospheric conditions were extended towards chocked vacuum conditions. An axisymmetric GDVN was considered fixed flow rate of 15 mg/min 40 µl/min. A mixture formulation...

Liquid micro-jets, produced from gas dynamic virtual nozzles (GDVNs), are used as sample carriers for interaction with X-ray beam in serial femtosecond crystallography (SFX). A numerical investigation of the effect focusing type on liquid micro-jet properties (its length and thickness) is presented. The study complements our previous research influence operating conditions nozzle geometry GDVN performance. helium, argon, carbon dioxide nitrogen gases (at a fixed mass flow rate 1.6 × 104...

Liquid micro-jets are crucial for sample delivery of protein crystals and other macromolecular samples in serial femtosecond crystallography. When combined with MHz repetition rate sources, such as the European X-ray free-electron laser (EuXFEL) facility, it is important that diffraction patterns collected before damaged. This requires extremely thin very fast jets. In this paper we first explore numerically influence different nozzle orifice designs on jet parameters finally compare our...

The present numerical study assesses the jet length, diameter and velocity of various non-Newtonian power-law fluids a gas dynamic virtual nozzle. A related two-phase flow problem is formulated within mixture framework solved with finite volume method fluid interface treatment in axisymmetry. process parametric range allows incompressible laminar assumption. comprehensive characteristics analysis carried out typical micro-nozzle configuration for shear-thinning to shear-thickening power law...

The results of an experimental study micro-jets produced with a gas dynamic virtual nozzle (GDVN) under the influence electric field are provided and discussed for first time. is performed 50% volume mixture water ethanol, nitrogen focusing gas. liquid sample Reynolds numbers range from 0.09-5.4 0-190, respectively. external electrode was positioned 400-500 μm downstream tip effect potential between 0-7 kV investigated. jetting parametric space examined as function operating flow rates,...

The performance of gas focused micro-jets is measured in terms stability, length, thickness, and speed. Such jets found use serial femtosecond crystallography (SFX) experiments performed at atmospheric pressure or vacuum. In this study, a numerical investigation the influence environmental on micro-jet presented. solution laminar, Newtonian, liquid-gas two-phase compressible model sought within finite volume method fluid framework. study conducted for constant liquid flow rates 22 µl/min 57...

Purpose – The purpose of this paper is to find solution Stokes flow problems with Dirichlet and Neumann boundary conditions in axisymmetry using an efficient non-singular method fundamental solutions that does not require artificial boundary, i.e. source points the coincide collocation on boundary. pressure velocity represents analytical due a singular Dirac delta infinite space. Design/methodology/approach Instead source, regularization parameter employed. Regularized axisymmetric sources...

In this paper we present a numerical study on the influence of liquid properties gas-focused micro-jets, such as used for sample delivery in serial femtosecond crystallography. The is based solving mixture formulation Newtonian, compressible two-phase model with finite volume method and algebraic fluid treatment phase-interface. density, viscosity surface tension focused span around material pure water range ±30%, thus representing large possible fluids. Fixed helium gas flow rates are jet...

The meshless Diffuse Approximate Method (DAM) is for the first time formulated and applied to simulate compressible Newtonian flow of an ideal gas in axisymmetric tube with varying cross-sections. problem structured by coupled partial differential equations conservation mass, momentum energy, equation state closure. These are solved primitive variables strong form. DAM on irregular node arrangement using second third-order polynomial shape functions Gaussian weights, leading weighted least...

Liquid micro-jets, produced from gas dynamic virtual nozzles (GDVNs), are used as sample carriers for interaction with X-ray beam in serial femtosecond crystallography (SFX). A numerical investigation of the effect focusing type on liquid micro-jet properties (its length and thickness) is presented. The study complements our previous research influence operating conditions nozzle geometry GDVN performance. helium, argon, carbon dioxide nitrogen gases (at a fixed mass flow rate 1.6 × 104...

This paper describes the development of Method Regularized Sources for potential flow problems. It is based on modification fundamental solution near source point by replacing singularity with a blob in form steep rational function. allows to solve problems same way as Fundamental Solutions, however without an artificial boundary. gives excellent results Dirichlet boundary conditions, it fails Neumann conditions. To overcome this problem are positions segments placed close collocation...

Purpose Double flow-focusing nozzles (DFFNs) form a coaxial flow of primary liquid with micro-crystalline samples, surrounded by secondary and focusing gas. This paper aims to develop an experimentally validated numerical model assess the performance micro-jets from DFFN as function various operating parameters for water–ethanol–helium system, revealing jet's stability, diameter, length velocity. Design/methodology/approach The physical is formulated in mixture-continuum formulation, which...

In this paper we present a numerical study on the influence of liquid properties gas-focused micro-jets, such as used for sample delivery in serial femtosecond crystallography. The is based solving mixture formulation Newtonian, compressible two-phase model with finite volume method and algebraic fluid treatment phase-interface. density, viscosity surface tension focused span around material pure water range ±30%, thus representing large possible fluids. Fixed helium gas flow rates are jet...

Abstract A meshless numerical model is developed to simulate single-phase, Newtonian, compressible flow in the Cartesian coordinate system. The coupled set of partial differential equations, i.e., mass conservation, momentum energy and equation state solved by using Diffuse Approximate Method (DAM) Pressure Implicit with Splitting Operators (PISO) pressure correction algorithm on an irregular node arrangement. DAM structured second-order polynomial basis functions Gaussian weight function,...