Small Nozzle Research Articles

Plant Movement Response to Environmental Mechanical Stimulation Toward Understanding Predator Defense.

Plants are fascinating living systems, possessing starkly different morphology to mammals, yet they have still evolved ways to defend themselves, consume prey, communicate, and in the case of plants like Mimosa pudica even move in response to a variety of stimuli. The complex physiological pathways driving this are of great interest, though many questions remain. In this work, a known responsive plant, M. pudica is mechanically stimulated, in terms of wounding via removal of pinnae, nonwounding mechanical poking, and nonwounding pulses of air through a designed small nozzle approach. Removal of clusters called pinnae resulted in rapid, asymmetric response in the adjacent pinnae, while mechanical poking and air pulse responses are slower and more localized. Additionally, while the response from poking propagated across the plant, wind stimuli consistently resulted in the actuation of only the leaflets directly stimulated, suggesting unique sensing mechanisms. Mechanical damage may imply a potential predator, while mechanical stimulation from airflow may be processed as wind, which is of little danger. These findings demonstrate an intricate, stimulant-dependent mechanical sensing process, which is important in plant physiology, mechanobiology, and future biohybrid soft robotic designs.

Optimizing rheological characterization for extrusion-based additive manufacturing of Zirconia ceramic inks with varied Yttria content stabilization

This study explores the rheological properties of zirconia-based ceramic inks, focusing on TZ-3YSB alongside newer variants such as Zpex, Zpex-4, and Zpex-smile, distinguished by their varying Y2O3 content. Through comprehensive analysis, it was found that these ceramic inks exhibit non-Newtonian behavior, which is notably influenced by the ceramic loading content and particle aggregation. Moreover, the shear-thinning nature observed in these inks proves advantageous, as it enables easier extrusion through smaller nozzles at reduced pressure levels. The implications of these findings are discussed in detail, shedding light on the complex interplay between rheological properties and ceramic ink composition, thus offering valuable insights for optimized three-dimensional printing (3DP) production processes - contributing to strengthening crowns, bridges, and implants, enhancing aesthetics, and ensuring biocompatibility for dental prostheses.

Load magnitude and location estimation on additively manufactured circular structures using deep learning

Additively Manufactured (AM) metal parts have been used at critical engineering applications. Estimation of load and its location is important to avoid accidents. Since the excitation signals move through multiple paths, estimation of load and its location is difficult. In this study, surface response to excitation method (SuRE) was implemented with multiple steps by considering the challenges of the geometry. Two 3D printed stainless steel rocket nozzle type structures with two different sizes and a C shaped tube section were used. Two different PZT placements were used for the big nozzle while the PZTs were located at the opposite sides of the small nozzle. The large nozzle had 280 test cases for 9 categories, while the smaller nozzle had 60 test cases for 5 categories. Finally, the C shaped specimen had 48 test cases for three categories. Continuous wavelet transform (CWT) was used to obtain more representative presentation of the data to the deep learning algorithm. Convolutional Neural Networks (CNNs) were used for classification. Wavelet transformation – Deep learning combination yielded 100 % accuracy for the large nozzle and 97.14 % for the smaller nozzle. These findings demonstrate the effectiveness of this technique on curved surfaces representative of real-world parts. The proposed method estimated the load location with 100 % accuracy.

Analysis of drop-on-demand printing characteristics and stability driven by inertial forces

As the core technology in the field of microdroplet related applications, researchers have been striving to develop new driving methods and improve the stability of inkjet printing technology to meet the diverse needs of various materials and applications. In this study, a novel, simple, and cost-effective droplet printing method based on inertial force driving is proposed, and its printing characteristics and stability are investigated through experimental and numerical simulation studies. A numerical model was developed to explore the effects of operating parameters and fluid properties on the printing process. The results showed that for a given fluid, it is easier to form satellite droplets when driven from a smaller nozzle with higher voltage and pulse width. The hydrophilic nature of the nozzle can suppress the formation of satellite droplets, but it is prone to retain liquid, thereby affecting the next printing effect. Under certain operating conditions, fluids with lower density, higher viscosity, and higher surface tension are difficult to be driven but can suppress the formation of satellite droplets and promote printing stability. Finally, a parameter space composed of dimensionless numbers Op representing operating parameters and Z representing fluid properties (reciprocal of the Oh number) was established to investigate the comprehensive influence on the printing. The correctness of this parameter space in guiding the selection of parameters for stable droplet printing was validated through experiments.

Molecular dynamics study of the sonic horizon of microscopic Laval nozzles.

A Laval nozzle can accelerate expanding gas above supersonic velocities, while cooling the gas in the process. This work investigates this process for microscopic Laval nozzles by means of nonequilibrium molecular dynamics simulations of stationary flow, using grand-canonical Monte Carlo particle reservoirs. We study the steady-state expansion of a simple fluid, a monoatomic gas interacting via a Lennard-Jones potential, through an idealized nozzle with atomically smooth walls. We obtain the thermodynamic state variables pressure, density, and temperature but also the Knudsen number, speed of sound, velocity, and the corresponding Mach number of the expanding gas for nozzles of different sizes. We find that the temperature is well defined in the sense that the each velocity components of the particles obey the Maxwell-Boltzmann distribution, but it is anisotropic, especially for small nozzles. The velocity autocorrelation function reveals a tendency towards condensation of the cooled supersonic gas, although the nozzles are too small for the formation of clusters. Overall we find that microscopic nozzles act qualitatively like macroscopic nozzles in that the particles are accelerated to supersonic speeds while their thermal motion relative to the stationary flow is cooled. We find that, like macroscopic Laval nozzles, microscopic nozzles also exhibit a sonic horizon, which is well defined on a microscopic scale. The sonic horizon is positioned only slightly further downstream compared to isentropic expansion through macroscopic nozzles, where it is situated in the most narrow part. We analyze the sonic horizon by studying space-time density correlations, i.e., how thermal fluctuations at two positions of the gas density are correlated in time and find that after the sonic horizon there are indeed no upstream correlations on a microscopic scale.

Beam Position Projection Algorithms in Proton Pencil Beam Scanning.

Beam position uncertainties along the beam trajectory arise from the accelerator, beamline, and scanning magnets (SMs). They can be monitored in real time, e.g., through strip ionization chambers (ICs), and treatments can be paused if needed. Delivery is more reliable and accurate if the beam position is projected from monitored nozzle parameters to the isocenter, allowing for accurate online corrections to be performed. Beam position projection algorithms are also used in post-delivery log file analyses. In this paper, we investigate the four potential algorithms that can be applied to all pencil beam scanning (PBS) nozzles. For some combinations of nozzle configurations and algorithms, however, the projection uses beam properties determined offline (e.g., through beam tuning or technical commissioning). The best algorithm minimizes either the total uncertainty (i.e., offline and online) or the total offline uncertainty in the projection. Four beam position algorithms are analyzed (A1-A4). Two nozzle lengths are used as examples: a large nozzle (1.5 m length) and a small nozzle (0.4 m length). Three nozzle configurations are considered: IC after SM, IC before SM, and ICs on both sides. Default uncertainties are selected for ion chamber measurements, nozzle entrance beam position and angle, and scanning magnet angle. The results for other uncertainties can be determined by scaling these results or repeating the error propagation. We show the propagation of errors from two locations and the SM angle to the isocenter for all the algorithms. The best choice of algorithm depends on the nozzle length and is A1 and A3 for the large and small nozzles, respectively. If the total offline uncertainty is to be minimized (a better choice if the offline uncertainty is not stable), the best choice of algorithm changes to A1 for the small nozzle for some hardware configurations. Reducing the nozzle length can help to reduce the gantry size and make proton therapy more accessible. This work is important for designing smaller nozzles and, consequently, smaller gantries. This work is also important for log file analyses.

Plasticizer-based and polymer-free ion-selective optodes on cellulose paper

Paper-based ion-selective optodes (ISOs) allow for low-cost ion measurements using widely accessible optical detectors such as smartphones, representing an attractive analytical platform for medical testing and environmental monitoring. Previously reported paper-based ISOs rely on plasticized PVC membranes or PVC/plasticizer-free adsorption layers containing hydrophobic sensing chemicals. In this paper, we studied a new format of paper-based ISOs, in which a plasticizer phase containing sensing chemicals is deposited onto cellulose paper without using a hydrophobic polymer like PVC. Compared to ISOs without plasticizers and polymers, the plasticizer-based ISOs show much higher pH sensitivity when using chromoionophore I and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate as the sensing chemicals. When the sensing layer further contains a solid ionophore with high molecular rigidity, the plasticizer-based ISOs for cations also exhibit enhanced sensitivity than the plasticizer-free ISOs. However, when the ionophore is a liquid at room temperature or has a long alkyl chain, the plasticizer-based and plasticizer-free ISOs have comparable responses because the ionophore behaves as a pseudo-plasticizer. Compared to ISOs with both plasticizers and polymers, the elimination of hydrophobic polymers like PVC makes inkjet printing more efficient and preserves the capillary action of the porous paper. By using the newly launched Samba cartridge with smaller nozzles, the plasticizer-based and polymer-free optodes for sodium, potassium, and calcium ions are prepared by inkjet printing for the first time. In an example application, the inkjet-printed plasticizer-based and polymer-free ISOs are used for colorimetric measurements of urine calcium.

A compact 3D printed magnetically stirred tank reactor cascade coupled with a free impinging jet for continuous production of colloidal nanoparticles

Most colloidal nanoparticle production processes involve more than one step, such as particle nucleation, growth and stabilisation, that often take place at different time scales. Flow chemistry offers an attractive platform for nanoparticle synthesis, as it can provide excellent control of conditions for each individual step. In this work, a free impinging jet reactor (FIJR), known for its rapid mixing capability and fouling-proof operation, is followed by a cascade of 5 miniaturised (3 ml) continuous stirred tank reactors (mCSTR) that provides longer residence time and efficient temperature control for subsequent synthesis steps, while still being resistant to clogging due to active mixing. The small (0.1 mm) diameter nozzle design allowed the FIJR to provide excellent mixing even at relatively low flowrates (2 ml/min/jet). The mCSTR cascade was arranged in a vertical configuration (one tank on top of another), offering a compact design that is simple to use and requiring only one magnetic stirrer. It provided near-ideal macromixing with limited dead volumes and interconnections, as reflected by a residence time distribution comparable with the theoretical one for a CSTR cascade. Most parts of the reactor system were 3D printed with features that facilitated the assembly. The proposed FIJR design overcomes the accuracy limitations of 3D printing by combining it with micromilling to achieve one of the smallest FIJR reported and by allowing for rotation of the nozzles to easily resolve issues with jet alignment. The reactor system was employed for the synthesis of colloidal (∼10 nm size) silver nanoparticles via NaBH4 reduction of AgNO3, in a 0.06 g/day scale for 50 min continuous operation and (∼6 nm core size) iron oxide nanoparticles via co-precipitation of Fe3+/Fe2+, producing colloidally stable nanoparticles in a 16.1 g/day scale for over 2 h continuous operation.

Numerical investigation of the thermal efficiency of a multi-nozzle air curtain doorway under different wind conditions

Loading gate openings cause thermal inefficiency due to the substitution of indoor–outdoor air in cold seasons, and as a consequence, escalating energy consumption of warehouse buildings or unloading docks. Research findings have demonstrated that air infiltration/exfiltration through open doors results in the loss of a quarter of annual heating loads in buildings. Air curtains have shown a bright and promising future to compensate for the infiltration rate through the door opening, however, the most prior investigations were allocated to the jet planar air curtains and as yet there is a gap in the literature for other modified air curtain devices, including multi-nozzle air curtains (MNAC) with higher induction and resistance against the strong frontal winds, especially for gates higher than 4.27 m of installation height. Hence, in this work, designed MNAC with various configurations (i.e. large nozzles, small nozzles and holes) and installed on a warehouse loading gate was first characterized using the validated numerical turbulence model, SST (k−ω), to solve governing equations. The validate model is then used to evaluate the MNAC thermal efficiency, using the sensible energy gained by the inside zone, under various outside temperatures (−5, −10, −20, and −30∘C), and two wind conditions (i.e. with and without a front wind as recommended by ASHRAE (2010)). While the air curtains demonstrated limitations in fully controlling the infiltration rate during extremely cold and windy conditions, the results indicate that the MNAC systems have obtained thermal efficiency values higher up to 10% when compared to conventional planar air jets.

The use of small diameter nozzles in temperature-controlled hemp oil extraction allows high oil yields and good quality residual hemp cake feed.

The use of two nozzle diameters (6 and 8 mm) in a cold (50°C) hemp seed oil extraction process was evaluated in terms of extraction efficiency, and chemical composition and in vitro fermentation characteristics of the residual cake. Seeds of the varieties Futura 75 and Uso 31 were pressed using a mechanical press with a cooling device. Five pressings were carried out for each variety and nozzle size, the functional parameters of the extraction processes were recorded, and sample of the residual cakes (n = 20) were analyzed. The 6 mm nozzle determined a higher oil yield (+4%) with a limited increase in temperature in the pressing chamber and in the oil (on average + 3°C compared to the 8 mm nozzle). A lower oil yield and consequently a higher fat content in the corresponding cake was observed when using the 8 mm nozzle. Despite the similar fat content, the two varieties had different oil yields and different residual cake compositions. The gas production kinetic of cakes was influenced by variety but little by nozzle size. Overall, the use of a smaller nozzle in a temperature-controlled extraction process can be a useful option to increase hemp oil yield while maintaining good fermentation characteristics of the residual cakes as ruminant feed.

A systematic approach to improve printability and cell viability of methylcellulose-based bioinks

Printability in 3D extrusion bioprinting encompasses extrudability, filament formation, and shape fidelity. Rheological properties can predict the shape fidelity of printed hydrogels. In particular, tan(δ), the ratio between loss (G′′) and storage (G′) modulus (G′′/G′), is a powerful indicator of printability. This study explores the effect of different salt, sucrose, and MC concentrations on tan(δ), and therefore the printability of methylcellulose (MC) hydrogels. Salt and sucrose increased G′, lowering tan(δ) and enabling printing of scaffolds with high shape fidelity. Conversely, MC concentration increased G′′ and G′, having a lesser effect on tan(δ). Shape fidelity of three formulations with similar G′ but varying tan(δ) values were compared. Higher tan(δ) led to reduced height, while lower tan(δ) improved shape fidelity. Cell viability increased when reducing MC content, extrusion rate, and nozzle gauge. Higher MC concentration (G′ > 1.5 kPa) increased the influence of needle size and extrusion rate on cell viability. Hydrogels with G′ < 1 kPa could be extruded at high rates with small nozzles, minimally affecting cell viability. This work shows a direct relationship between tan(δ) and printability of MC-based hydrogels. Lowering the complex modulus of hydrogels, mitigates extrusion stress, thus improving cell survival.

Numerical investigation of nozzle shape effect on the flash boiling phenomenon

Small nozzles may be used as an element of novel steam traps in steam heating systems or shell-coil (JAD) heat exchangers. Phenomena occurring in these nozzles should be analyzed to find their optimal operating points and avoid steam losses. Therefore, the paper presents a numerical investigation of the effect of the nozzle shape on the flash boiling phenomena. Particularly, the study aimed to check the relation between the shape of the decompression part of the nozzle and the mass flow rate of the mixture of water and vapor flowing through it for different pressures and undercooling of water at the nozzle inlet. Two geometries of the divergent part of the nozzle, i.e. the stepped and conical, were considered. In the analysis, two-phase flow in the decompression part of the nozzle was accounted for by applying the mixture model. The dynamics of the phase change process during the flash boiling were described with the Zwart-Gerber-Belamri model, additionally supplied with the polynomial relationship linking the saturation pressure and temperature of the water. In the first step, a credibility analysis of the model was conducted. The simulated results were compared to the literature’s reference results, and a good agreement was achieved. Moreover, the independence of results on the grid size and turbulence modeling in the bulk flow and near-wall region was shown. In the second step, a series of simulations were carried out for both nozzle geometries (stepped and conical), three nozzle neck diameters, three pressures, and eleven undercooling of water at the inlet to the nozzle. The shape of the divergent part of the nozzle was found to influence the characteristics of flash boiling flow significantly. However, it did not affect the mass flow rate of water flashing through the nozzle. For both geometries, the predicted mass flow rates were the same.

Characterizations and Inkjet Printing of Carbon Black Electrodes for Dielectric Elastomer Actuators.

Dielectric elastomer actuators (DEAs) have been proposed as a promising technology for developing soft robotics and stretchable electronics due to their large actuation. Among available fabrication techniques, inkjet printing is a digital, mask-free, material-saving, and fast technology, making it versatile and appealing for fabricating DEA electrodes. However, there is still a lack of suitable materials for inkjet-printed electrodes. In this study, multiple carbon black (CB) inks were developed and tested as DEA electrodes inkjet-printed on acrylic membranes (VHB). Triethylene glycol monomethyl ether (TGME) and chlorobenzene (CLB) were selected to disperse CB. The inks' stability, particle size, surface tension, viscosity, electrical resistance, and printability were characterized. The DEA with Ink-TGME/CLB (mixture solvent) electrodes obtained 80.63% area strain, a new benchmark for the DEA actuation with CB powder electrodes on VHB. The novelty of this work involves the disclosure of a new ink recipe (TGME/CLB/CB) for inkjet printing that can obtain stable drop formations with a small nozzle (17 × 17 μm), high resolution (∼25 μm, approaching the limit of drop-on-demand inkjet printing), and the largest area strain of DEAs under similar conditions, distinguishing this contribution from the previous works, which is important for the fabrication and miniaturization of DEA-based soft and stretchable electronics.

Controlled Bubble Formation From a Microelectrode Single Bubble Generator

Abstract In this work, a new micro-electrode bubble generator is presented that employs a micro-electrode installed inside a small nozzle enabling the production of bubbles with controllable size and frequency. This bubble generator can be employed as a simple and potentially cheap method for the generation of single bubbles in a liquid, as long as it enables ion exchange, as an alternative to more complicated methods such as timely injection of a gas through a nozzle, which requires sophisticated nozzle design, manufacturing, and monitoring of the injected gas flow rate. A systematic investigation was conducted to assess the effect of the bubble generator dimensions, applied voltage, and electrolyte flow conditions on the size and frequency of the generated bubbles. It was shown that when the micro-electrode is thinly concealed within the nozzle, this bubble generator can successfully produce bubbles covering a wide range of diameters from 0.4 to 1.4 mm with a size distribution standard deviation of about 25%. The mechanism of single and continuous bubbles formation from the proposed bubble generator is also discussed. While this paper introduces this new micro-electrode bubble generator, further work is required to optimize it, enabling more accurate control over bubble size and frequency.

A mixed numerical-experimental study of the outdoor wind effects on the indoor air distribution under the multi-nozzle air curtains

The infiltration of cold air through the open doors is controlled using air curtains, resulting in lower thermal loss and higher energy efficiency in the buildings. Meanwhile, severe outdoor conditions affect the performance of the air curtains drastically. In this context, the performance of a multi-nozzle air curtain with two different geometries has been investigated under various outdoor conditions using validated CFD. The air curtain system creates a thermal barrier with a specific sequence of large nozzles, small nozzles, and holes that blow air downward at different speeds. A half scale (1:2) model located above a door in the middle of the wind tunnel at the University of Sherbrooke is used for the hot wire measurements of the critical characteristics for different wind velocities (0, 4, and 9 m/s). Also, the SST k−ω turbulence model has shown the highest accuracy during the turbulence model sensitivity analysis and is used for complementary studies. Despite all the similarities, the results indicate that Fifth Order Polynomial Nozzles are more resistant against the high-velocity front winds, comparing the Arc Shape Nozzles, due to 3.6% augmentation of the exit velocities at large nozzles and shorter convergence areas. Also, this fact is proven by the studies of the impact point of these air curtains.

Colinear focused laser differential interferometry and self-aligned focusing schlieren.

A colinear focused laser differential interferometer (FLDI) and self-aligned focusing schlieren (SAFS) system has been assembled and tested in the laboratory, using a turbulent jet of compressed air issuing from a small needle nozzle to provide a high frequency density object. Measurements verified that the coupling of the SAFS system onto the optical axis of the FLDI system had negligible influence on the FLDI system's data, including tests that assessed the influence of the inclusion of dichroic mirrors, dichroic mirror reflection angle, dichroic mirror positioning relative to the Wollaston prisms of the FLDI system, and SAFS light propagation direction. A qualitative comparison of the focusing ability of the two systems was made, and FLDI power spectral density estimates and SAFS spectral proper orthogonal decomposition were used for quantitative comparisons of the acoustic frequency of the jet, with good agreement between the two. The success of the system integration and resulting jet testing demonstrates the utility of this colinear, simultaneous FLDI/SAFS measurement system.

Optimal design of a novel nested-nozzle ejector for PEMFC's hydrogen supply and recirculation system

The ejector-based hydrogen supply and recirculation system (HSRS) for a Proton Exchange Membrane Fuel Cell (PEMFC) system has the advantages of compact size and zero power consumption, compared with the HSRS using a recirculation pump. However, the conventional ejector with a single venturi nozzle can only function within a narrow power range of the PEMFC system due to its restricted primary inlet pressure. This study proposed a novel ejector design with nested nozzles to solve this problem. The key geometric parameters, including the nozzle diameters of a large nozzle (BN), a small nozzle (SN), and the axial distance between two nozzles, were optimized using CFD simulations to obtain the maximum entrainment capability. The BN mode is responsible for the stack's higher load operations, while the SN mode supports the lower power operations. Additionally, a bypass was used parallel to the nested-nozzle ejector in the HSRS to extend the ejector operating range further. The consistent CFD simulation and testing results of the nested-nozzle ejector showed effective hydrogen entrainment capability between 9% and 100% of power output for a 150 kW PEMFC stack. Moreover, the new nested-nozzle ejector HSRS showed much-reduced anode inlet pressure fluctuation compared to the HSRS using two conventional ejectors.

Nanoscopic jets and filaments of superfluid 4He at zero temperature: A DFT study.

The instability of a cryogenic 4He jet exiting through a small nozzle into vacuum leads to the formation of 4He drops, which are considered ideal matrices for spectroscopic studies of embedded atoms and molecules. Here, we present a He-density functional theory (DFT) description of droplet formation resulting from jet breaking and contraction of superfluid 4He filaments. Whereas the fragmentation of long jets closely follows the predictions of linear theory for inviscid fluids, leading to droplet trains interspersed with smaller satellite droplets, the contraction of filaments with an aspect ratio larger than a threshold value leads to the nucleation of vortex rings, which hinder their breakup into droplets.

Sustainable 3D printing of oral films with tunable characteristics using CMC-based inks from durian rind wastes

With the growing interest in environmentally friendly and personalized medicines, new concept for combining three-dimensional printing (3DP) with natural-based biomaterials derived from agro-food wastes has emerged. This approach provides sustainable solutions for agricultural waste management and potential for developing of novel pharmaceutical products with tunable characteristics. This work demonstrated the feasibility of fabricating personalized theophylline films with four different structures (Full, Grid, Star, and Hilbert) using syringe extrusion 3DP and carboxymethyl cellulose (CMC) derived from durian rind wastes. Our findings suggested that all the CMC-based inks with shear thinning properties capable of being extruded smoothly through a small nozzle could potentially be used to fabricate the films with various complex printing patterns and high structural fidelity. The results also demonstrated that the film characteristics and release profiles could be easily modified by simply changing the slicing parameters (e.g., infill density and printing pattern). Amongst all formulations, Grid film, which was 3D-printed with 40 % infill and a grid pattern, demonstrated a highly porous structure with high total pore volume. The voids between printing layers in Grid film increased theophylline release (up to 90 % in 45 min) through improved wetting and water penetration. All findings in this study provide significant insight into how to modify film characteristics simply by digitally changing the printing pattern in slicer software without creating a new CAD model. This approach could help to simplify the 3DP process so that non-specialist users can easily implement it in community pharmacies or hospital on demand.

Experimental and numerical study of heat transfer under laminarization condition in a small size supersonic nozzle

The present paper compares measured and calculated heat transfer parameters for a small-size slot supersonic nozzle. Heat transfer coefficient and temperature recovery factor were examined under conditions of partial laminarization of boundary layer caused by moderate flow acceleration and low Reynolds numbers. The transient heat transfer method was implemented for estimation of these values for the nozzle subsonic and supersonic parts. Maximum values of flow acceleration parameter K lied in the range 1.3 … 2.75∙10−6. Experimentally measured value was normalized to the developed turbulent boundary layer heat transfer coefficient and reached St/StRex = 0.5–0.7 and indicated partial laminarization phenomenon. It was shown that the temperature recovery factor hasn't been affected by the flow acceleration. The results are compared to numerical heat transfer predictions using sst, γ-sst and γ-Reθ-sst turbulence models. Numerical calculations and experimental data were found to be in reasonably good agreement for low acceleration level with K less than 0.75∙10−6. Nevertheless, γ-sst turbulence model made slightly conservative estimation whereas in contrast γ-Reθ-sst model overestimates quantities for the moderate flow acceleration conditions.