Non-moving Parts Research Articles

Preliminary Design of a Ramjet Engine: An Analytical Approach

This work is based on preliminary design of Ramjet engine. Ramjet engine is simplest type of gas turbine engine used, which consists of non-moving parts for its operation. It is mainly used for power generation at supersonic speeds. This type of engine is mostly used in missiles, with a few applications in aircrafts. The present approach to preliminary design was based on mathematical equations considering ideal conditions. For the design, aero-thermodynamic equations were used starting with intake and followed by diffuser, combustor and nozzle. For the design purpose, initially Mach 2 and thrust of 10 kN was selected as desired condition. Subsequently, it was analyzed for the varying Mach numbers starting from Mach 1.5 to Mach 4 at desired thrust of 10 kN. Also, the design was analyzed for varying thrust from 6 kN to 22 kN at desired Mach number of 2. The results obtained have been reported and effects of variation of parameters have been represented graphically. The graphs were obtained using GNU Octave 6.4.0. The design achieved could be used for further steps of CAD model generation and subsequent analysis for the required purpose. It can serve as a base for detailed design of the engine.

Constructing assembly design model capable of capturing and sharing semantic dynamic motion information in heterogeneous CAD systems

Over the last decades, collaborative assembly design has received much attention, which has provided fruitful results in terms of data models, knowledge-based, and top-down geometric modeling approaches, to name a few. Particularly, researchers have focused their efforts towards assembly relationships within product models, but have limited the scope to static assembly geometric description as currently stated in computer-aided design (CAD) systems. A disruptive vision is assumed in this research work, arguing that the assembly design itself presents a dynamic nature via, especially, dynamic motion. Such a paradigm shift requires an appropriate logical and semantic foundation to augment current CAD systems and data models’ capabilities with the capture of dynamic phenomena such as assembly motions and kinematic behaviors. Traditional CAD systems nowadays can handle the kinematics-related motion-related information; however, the interoperation of this motion-related information from one CAD system to the other is still a limitation of the interoperability standards. To tackle this research challenge, this paper aims at defining an original framework built upon a formal ontology to capture and share dynamic assembly motion among heterogeneous CAD systems. The formal ontology uses spatiotemporal mereotopology, which serves as a theoretical backbone to qualitatively describe the dynamic behavior of a product. This theory addresses the qualitative description of the temporal dimension over the spatial dimension of 3D objects. The proposed ontology is then enhanced to maintain semantic continuity of the spatial and temporal aspects embedded in assembly design ontology models. Built with a Web Ontology Language (OWL) data structure to interact with a CAD system and a motion visualization application, the ontology ensures the dynamic motion information capturing and sharing. SWRL (Semantic Web Rule Language) is utilized to show the semantic reasoning among the moving and non-moving parts of the product assembly. As a result, a semantic articulation ensuring flexibility and interoperability as a competitive industrial edge is demonstrated with proof of concept to be effective in a collaborative assembly design environment.

Performance of ejector refrigeration cycle based on solar energy working with various refrigerants

The refrigerator unit based on electrically driven vapor compression technology consumes high energy, associated with high cost and loss of ecosystem. Recently, solar thermal energy emerges as a key research area and introducing it in refrigerator application has happened extremely fast. Solar thermal refrigeration systems based on ejector compression technology are thriving because of its utilization of low-grade energy sources, straight forward design, non-moving parts, lower maintenance costs, and durability. In this present work, the performance of a solar ejector refrigeration system (ERS) is calculated analytically using one-dimensional model. The performance parameters are calculated with the assumption that both the condensation and evaporation processes occur along the saturation line. Initially, the influence of the ejector area ratio, generator temperature, condenser temperature, and evaporator temperature on the performance of the ERS is analyzed in critical mode with water (R718) as the working fluid. The analysis shows that the coefficient of performance increases more than two times on increasing the ejector area ratio from 6.4 to 12.8. The results also show that a higher coefficient of performance (COP) is obtained at a higher ejector area ratio. The COP is found to be inversely related to the generator temperature, meanwhile the coefficient of performance increase more than 74% on increasing the refrigeration temperature from Tc = 8 °C to Tc = 15 °C. Then, the performance of ERS is obtained at the subcritical conditions at varying generator temperatures. At subcritical mode, COP is found to be directly proportional to the generator temperature, and the highest COP occurs at an optimum generator temperature. The performance of the ERS with various refrigerants as R717, R718, R245fa, R123, R141b, and R365fa is calculated at the critical mode. With refrigerant R717, the system shows higher performance as well as a cooling effect than other refrigerants. However, most environmental benign refrigerant R718 shows comparatively low performance, but it is found that R718 produces a significant cooling effect than other refrigerants excluding R717 refrigerant.

Numerical simulation and experimental investigation of air cooling system using thermoelectric cooling system

Efficient air-conditioning inside the cars is a challenge in automobile industry. Thermoelectric is one of the new methods for air cooling. It has many advantages such as non-moving parts, small size, low weight, fluid less functions, and dealing with direct current source. This research aimed to determine the amount of air chamber cooling using three thermoelectrics. For this purpose, air cooling system was initially developed and then simulated by ANSYS CFX software. The system was tested at three different airflow (0.18, 0.35 and 0.7 m s−1) and three different inlet air temperatures (31, 40 and 50 °C). The temperatures of the four points were recorded. The results of numerical simulation were compared with the experimental ones. This research demonstrated that thermoelectrics can be a good choice for air cooling. However to improve the performance of this system, it is recommended to change the layout of the heat sinks. Furthermore, the mean difference between the result of the numerical simulation and that of the experimental tests was 8.5% indicating that this simulation can be promising with sufficient confidence.

Determination of Oil Change Interval for Gasoline Engines According to the Amount of Non-Ferrous Metals

Friction is closely related to every moving machine and fundamentally affects efficiency and service life. Wear tracking of moving and non-moving parts of the engine mechanism is important for expressing the wear trend. The wear and tear trend is specific for gasoline engines in urban traffic. The increase in the number of abrasive non-ferrous particles (Al, Cu, Ni, Cr, Sn, Si) is monitored in Ĺ koda Octavia vehicles. The statistical evaluation of nomogram the wear and the determination of the optimum oil change interval of a vehicle group with sparkignition engines are performed for individual non-ferrous particles. The main aim of the article is to propose and verify the method of determination of the optimal oil change interval using Atomic Absorption Spectroscopy, Thin Layer Chromatography and using limit values of discriminatory analysis. On the basis of the results of the analyses, it is clear that the oil change interval by the manufacturer is inadequate and the oil level must be monitored.

3D Backward-Facing Step Flow Structure Modification with Plasma Actuators

Backward-Facing Step (BFS) shape is a common configuration found in several engineering applications. The turbulent flow structure in the backside of a BFS leads to risky situations. Then, flow control is a useful technique to achieve safe conditions. In recent years, plasma devices have become an interesting technology with high importance for flow control because of non-moving parts, fast time response and low energy consumption. This paper presents the experimental investigation of a set of Dielectric Barrier Discharge (DBD) plasma actuators placed on the rounded edge of a BFS and its capability for flow control by wind tunnel testing. In contrast to the other studies, the behaviour of the plasma actuators in presence of 3D flow over a BFS was investigated. Firstly, a parametric study by analysing the location and the influence of the electrical parameters of the DBD plasma actuator was performed at a freestream velocity of 6 m/s using Particle Image Velocimetry (PIV). It was seen that actuator with -45° wall jet provides the highest flow control at 30 kVpp and 2.5 kHz with a reattachment length reduction of 65.6% referred to plasma off case. This configuration was optimized and compared with a double actuator for a higher velocity (10 m/s). The manufacturing complexity of the double actuator recommends the use of a simple actuator due to the fact that they have similar results, with a 30% of reattachment point reduction approximately at 10 m/s. Anyhow, the results confirm the authority of plasma actuators to modify the flow structure behind a BFS.

Non-moving scanner design for OCT systems.

In this work, a novel beam scanner design based on non-moving parts is introduced which will eliminate the phase and inaccuracy problems of the mechanical scanners while providing two times imaging speed improvement for optical coherence tomography systems. The design is comprised of electro-optically activated switches that are placed on the sample arm. For the example considered here, lateral resolution of 20 µm, and lateral scanning range of 1 mm are aimed at which resulted in a scanner size of 1 mm × 9 mm. Due to its compact size, proposed design can also be implemented in forward-looking endoscopic probes.

Robust non-blind color video watermarking using QR decomposition and entropy analysis

Issues such as content identification, document and image security, audience measurement, ownership and copyright among others can be settled by the use of digital watermarking. Many recent video watermarking methods show drops in visual quality of the sequences. The present work addresses the aforementioned issue by introducing a robust and imperceptible non-blind color video frame watermarking algorithm. The method divides frames into moving and non-moving parts. The non-moving part of each color channel is processed separately using a block-based watermarking scheme. Blocks with an entropy lower than the average entropy of all blocks are subject to a further process for embedding the watermark image. Finally a watermarked frame is generated by adding moving parts to it. Several signal processing attacks are applied to each watermarked frame in order to perform experiments and are compared with some recent algorithms. Experimental results show that the proposed scheme is imperceptible and robust against common signal processing attacks.

Thermoelectric Generators for the Integration into Automotive Exhaust Systems for Passenger Cars and Commercial Vehicles

A special thermoelectric generator system design and the setup of a thermoelectric generator for the integration into the exhaust line of combustion engine-driven vehicles are described. A prototype setup for passenger cars and the effects on the measured power output are shown. Measurement results using this setup show the potential and the limitations of a setup based on thermoelectric modules commercially available today. In a second step, a short outline of the detailed mathematical modeling of the thermoelectric generator and simulation studies based on this model are presented. By this means, it can be shown by which measures an improvement of the system power output can be achieved—even if today’s modules are used. Furthermore, simulation studies show how the exhaust gas conditions of diesel- and Otto-engines significantly affect the requirements on thermoelectric materials as well as the potential and the design of the thermoelectric generator. In a further step, the design and the setup of a thermoelectric generator for an application in a commercial vehicle are presented. This thermoelectric generator is designed to be integrated into the exhaust aftertreatment box of the vehicle. Experimental results with this setup are performed and presented. The results show that thermoelectric generators can become an interesting technology for exhaust waste heat recovery due to the fact that they comprise non-moving parts. However, the efficiency of the modules commercially available today is still far from what is required. Hence, modules made of new materials known from laboratory samples are urgently required. With regard to future CO2 regulations, a large market opportunity for modules with a high efficiency can be expected.

일반화된 4차원 특징을 이용한 행동 방향 인식

본 논문에서는 4차원 시공간 (4D-ST, [x,y,z,t]) 특징을 이용하여 행동 방향을 인식하는 방법을 제안한다. 이를 위해 4차원 시공간 특징점 (4D-STIPs, [x,y,z,t])을 제안하였고, 이는 여러 다른 뷰에서 촬영한 이미지들로부터 복원된 3차원 공간 (3D-S, [x,y,z]) 볼륨으로부터 계산된다. 3차원 공간정보를 갖고 있는 3D-S 볼륨과 4D-STIPs는 2차원 공간 (2D-S, [x,y]) 뷰로 사영을 하여 임의의 2D-S 뷰에서의 특징을 생성해 낼 수 있다. 이 때, 사영 방향을 결정 할 수 있으므로, 학습 시 방향에 대한 정보를 포함하여 행동 방향을 인식 할 수 있다. 행동 방향을 인식하는 과정은 두 단계로 나눌 수 있는데, 우선 어떤 행동인지를 인식하고 그 후, 방향 정보를 이용하여 최종적으로 행동 방향을 인식한다. 행동 인식과 방향 인식을 위해, 사영된 3D-S 볼륨과 4D-STIPs은 각각 움직이는 부분과 움직이지 않는 부분에 대한 정보를 담고 있는 motion history images (MHIs)와 non-motion history images (NMHIs)로 구성된다. 이러한 특징들은 행동 인식을 위해, 방향 정보에 상관없이 같은 행동이면 같은 클래스로 분류되어 support vector data description (SVDD) 분류기로 학습되고, support vector domain density description (SVDDD)을 이용하여 인식된다. 인식된 행동에서 최종적으로 방향을 인식하기 위해 각 행동을 방향 클래스로 분류하여 SVDD 분류기로 학습하고 SVDDD로 인식한다. 제안된 방법의 성능을 보이기 위해서 INRIA Xmas Motion Acquisition Sequences (IXMAS) 데이터셋에서 제공하는 3D-S 볼륨을 사용하여 학습을 하고, 행동 방향 인식 실험이 가능한 SNU 데이터셋을 구축하여 인식 실험을 하였다. In this paper, we propose a method to recognize the action direction of human by developing 4D space-time (4D-ST, [x,y,z,t]) features. For this, we propose 4D space-time interest points (4D-STIPs, [x,y,z,t]) which are extracted using 3D space (3D-S, [x,y,z]) volumes reconstructed from images of a finite number of different views. Since the proposed features are constructed using volumetric information, the features for arbitrary 2D space (2D-S, [x,y]) viewpoint can be generated by projecting the 3D-S volumes and 4D-STIPs on corresponding image planes in training step. We can recognize the directions of actors in the test video since our training sets, which are projections of 3D-S volumes and 4D-STIPs to various image planes, contain the direction information. The process for recognizing action direction is divided into two steps, firstly we recognize the class of actions and then recognize the action direction using direction information. For the action and direction of action recognition, with the projected 3D-S volumes and 4D-STIPs we construct motion history images (MHIs) and non-motion history images (NMHIs) which encode the moving and non-moving parts of an action respectively. For the action recognition, features are trained by support vector data description (SVDD) according to the action class and recognized by support vector domain density description (SVDDD). For the action direction recognition after recognizing actions, each actions are trained using SVDD according to the direction class and then recognized by SVDDD. In experiments, we train the models using 3D-S volumes from INRIA Xmas Motion Acquisition Sequences (IXMAS) dataset and recognize action direction by constructing a new SNU dataset made for evaluating the action direction recognition.

Systemic toxicity related to metal hip prostheses

Introduction. One in eight of all total hip replacements requires revision within 10 years, 60% because of wear-related complications. The bearing surfaces may be made of cobalt/chromium, stainless steel, ceramic, or polyethylene. Friction between bearing surfaces and corrosion of non-moving parts can result in increased local and systemic metal concentrations. Objectives. To identify and systematically review published reports of systemic toxicity attributed to metal released from hip implants and to propose criteria for the assessment of these patients. Methods. Medline (from 1950) and Embase (from 1980) were searched to 28 February 2014 using the search terms (text/abstract) chrom* or cobalt* and [toxic* or intox* or poison* or adverse effect or complication] and [prosthes* or ‘joint replacement’ or hip or arthroplast*] and PubMed (all available years) was searched using the search term ((“Chromium/adverse effects”[Mesh] OR “Chromium/poisoning”[Mesh] OR “Chromium/toxicity”[Mesh]) OR (“Cobalt/adverse effects”[Mesh] OR “Cobalt/poisoning”[Mesh] OR “Cobalt/toxicity”[Mesh])) AND (“Arthroplasty, Replacement, Hip”[Mesh] OR “Hip Prosthesis”[Mesh]). These searches identified 281 unique references, of which 23 contained original case data. Three further reports were identified from the bibliographies of these papers. As some cases were reported repeatedly the 26 papers described only 18 individual cases. Systemic toxicity. Ten of these eighteen patients had undergone revision from a ceramic-containing bearing to one containing a metal component. The other eight had metal-on-metal prostheses. Systemic toxicity was first manifest months and often several years after placement of the metal-containing joint. The reported systemic features fell into three main categories: neuro-ocular toxicity (14 patients), cardiotoxicity (11 patients) and thyroid toxicity (9 patients). Neurotoxicity was manifest as peripheral neuropathy (8 cases), sensorineural hearing loss (7) and cognitive decline (5); ocular toxicity presented as visual impairment (6). All these neurological features, except cognitive decline, have been associated with cobalt poisoning previously. Type of prosthesis and blood metal concentrations. Where blood or serum metal concentrations were reported (n = 17 for cobalt and n = 14 for chromium), the median cobalt concentration was 398 (range, 13.6–6521) μg/L and the median chromium concentration was 48 μg/L (in whole blood) (range, 4.1–221 μg/L including serum and blood values). Those patients reported to have systemic features who had received a metal-on-metal prosthesis (n = 8) had a median peak blood cobalt concentration of 34.5 (range, 13.6–398.6) μg/L; those with a metal-containing revision of a failed ceramic prosthesis (n = 10) had a median blood cobalt concentration of 506 (range, 353–6521) μg/L. Management. The most common treatment was removal of the metal-containing prosthesis, undertaken in all but 2 patients. This was usually associated with a fall in circulating cobalt concentration and improvement in some or all features. Clinical and toxicological assessment of systemic features. We propose the following criteria for assessing the likelihood that clinical features are related to cobalt toxicity: clinical effects consistent with the known neurological, cardiac, or thyroidal effects of cobalt, and for which any other explanation is less likely; increased blood cobalt concentrations (substantially higher than those in patients with well-functioning prostheses) several months after hip replacement; a fall in the blood cobalt concentration, usually accompanied by signs of improvement in features. When judged by these criteria, the systemic features in 10 of the reported cases are likely to be related to cobalt exposure from a metal-containing hip prosthesis. Conclusions. Rarely, patients exposed to high circulating concentrations of cobalt from failed hip replacements develop neurological damage, hypothyroidism and/or cardiomyopathy, which may not resolve completely even after removal of the prosthesis. The greatest risk of systemic cobalt toxicity seems to result from accelerated wear of a cobalt-containing revision of a failed ceramic prosthesis, rather than from primary failure of a metal-on-metal prosthesis.

View invariant action recognition using generalized 4D features

In this paper, we propose a method to recognize human actions independently of viewpoints by developing 4D space–time features which can generalize the information from a finite number of views in training phase so as to show a satisfactory performance in arbitrary testing views. This 4D space–time interest points (4D-STIPs, [x,y,z,t]) are extracted using 3D space volumes reconstructed from images of a finite number of different views. Since the proposed features are constructed using volumetric information, the features for arbitrary 2D space viewpoint in testing can be generated by projecting the 3D space volumes and 4D-STIPs on corresponding test image planes. This enables action recognition in any camera viewpoint even after training with images from only a finite number of views. We also propose the variant of 3D space–time interest points, which take into account the simultaneous gradient variation in all 3 dimensions to focus on the motion of important spatial corner points. 3D space volumes and 4D-STIPs can be projected to arbitrary viewpoints for training each action to get generalization capability of the classifier. With these projected features, we construct motion history images and non-motion history images which encode the moving and non-moving parts of an action respectively. After reducing the feature dimension, the final features are learned by support vector data description method. In experiments, we train the models using IXMAS dataset constructed from five views and test them with a new SNU dataset made for evaluating the generalization performance for arbitrary view videos.

Experimental Characterization of the Plasma Synthetic Jet Actuator

The plasma synthetic jet is a novel active flow control method because of advantages such as fast response, high frequency and non-moving parts, and it has received more attention recently, especially regarding its application to high-speed flow control. In this paper, the experimental characterization of the plasma synthetic jet actuator is investigated. The actuator consists of a copper anode, a tungsten cathode and a ceramic shell, and with these three parts a cavity can be formed inside the actuator. A pulsed-DC power supply was adopted to generate the arc plasma between the electrodes, through which the gas inside was heated and expanded from the orifice. Discharge parameters such as voltage and current were recorded, respectively, by voltage and current probes. The schlieren system was used for flow visualization, and jet velocities with different discharge parameters were measured. The schlieren images showed that the strength of plasma jets in a series of pulses varies from each other. Through velocity measurement, it is found that at a fixed frequency, the jet velocity hardly increases when the discharge voltage ranges from 16 kV to 20 kV. However, with the discharge voltage fixed, the jet velocity suddenly decreases when the pulse frequency rises above 500 Hz, whereas at other testing frequencies no such decrease was observed. The maximum jet velocity measured in the experiment was up to 110 m/s, which is believed to be effective for high-speed flow control.

Design Optimization of Linear Generator for a Hydrokinetic Energy Converter

The power take off (PTO) mechanism for a vortex induced vibration (VIV) based hydrokinetic energy converter discussed here is a linear generator. The power take off system is one of the most important systems of the converter which is responsible for the conversion of mechanical energy into useful electrical energy. This paper deals with optimization of the design of the linear generator in areas such as materials of construction, engineering design, water proofing, magnetic configuration, air-gap reduction, durability and cost-effectiveness. The linear generator consists of moving and non-moving parts and its working environment is a fluid which is generally water. The main challenges include complete water-proofing of the entire linear generator, reduction of weight of the moving part, smoother motion of the moving part over the non-moving part, corrosion protection of all metal parts and sustenance of intensity of the magnetic field strength. The proposed design aims to address these challenges and increase the efficiency of the overall system.

Self-tuning laser speckle contrast analysis based on multiple exposure times with enhanced temporal resolution

Laser Speckle Contrast Analysis (LASCA) was introduced in 1981. Since then, several enhancements were applied to it. Nowadays, the technique can provide relatively high accuracy as well as high temporal and spatial resolution during the examination of ocular or cerebral tissues. However, in the case of skin, the results are highly affected by the intensive scattering on the skin surface, as the scattering on the non-moving parts of the sample lead to the detrimental decrease of the accuracy. We present a LASCA method based on the use of multiple exposure times, combined with the switching-mode control of the light intensity and a special sampling technique to achieve near to real-time measurement of the skin perfusion. The system based on our method is able to automatically handle the destructive effect of the skin surface and re-tune itself according to the changes of the sample, while it provides full-field perfusion maps with high accuracy, without the need of any precalibrations.

MHD printhead for additive manufacturing of metals

Within the scope of additive manufacturing of metal parts, a droplet generator for metal melts is proposed. Its magnetohydrodynamic (MHD) working principle is shown and the actuation force available for droplet generation is calculated. The design of such a printhead is shown to consist only of very few, non-moving parts and therefore it is of great simplicity. First results gained with a prototype printhead show that successful droplet generation is possible, but that pollution of the melt with oxides and sparks developing during the droplet generation process have to be overcome to fully exploit the potential of the proposed print head.

Characterization and performance of the electroosmotic pumping effect for different porous media

High flow rate electroosmotic, EO, pumps are of great interest due to their simple design and non-moving parts. EO pumps were fabricated from two types of membranes: a never before tested, microcapillary array and the popular, anodic aluminum oxide (AAO). Flow rates and power consumption were measured directly for both membranes while efficiency was measured indirectly for the AAOs. A normalized flow rate of 1.90 mL/min/V/cm2 was recorded which is the highest normalized flow rate published. Large inefficiencies can occur due to electrolysis and electrode spacing and thus methods to decreasing these problems are discussed. Electroosmotic pumps were driven by constant voltage and asymmetric voltage pulses. The asymmetric voltage pulses negated electrolysis while producing a net flow. Voltage losses due to electrode spacing were minimized by platinum coatings.

Tripod stiffening using clamping plates with no increase of moving mass

In this paper, a new method is presented for stiffening a tripod made of fixed-length legs. The idea is to add a pair of clamping plates to each leg. In doing so, the out-of-plane motion of the leg is fully constrained, thereby significantly increasing its bending stiffness. Compared to the existing designs, the advantage of this new design is that the clamping plates are the non-moving parts, therefore not contributing to the moving mass. As a result, the tripod can still be made very compact with light moving mass. To facilitate the design of the clamping plates, a method is proposed for analyzing the workspace of the sliding leg so that the shape of the clamping plates and the location of the clamping point can be properly selected. This design has been implemented on an existing tripod for polishing applications. Both theoretical and experimental results have shown the effectiveness of this new design.

Surrogate modelling for characterising the performance of a dielectric barrier discharge plasma actuator

The dielectric barrier discharge (DBD) plasma actuator offers promising opportunities for flow control because of its fast response and non-moving parts. In this work, surrogate modelling is adopted to better understand the impact of the materials and operational parameters on the actuator performance, and to provide an efficient approach for performance estimation. The DBD model based on 2-species helium chemistry engages three design variables: operating frequency, polarity (positive/negative) time ratio of the applied voltage and the dielectric constant of the insulator. Two objectives are identified: the net force generated and the power requirement. Multiple surrogate models are used, which identify two branches of the Pareto front with opposite net force direction and substantially different parametric sensitivities. Global sensitivity analysis indicates that the voltage frequency and polarity ratio are important in different regions of the design space, while the dielectric constant is always important.

T0501-4-4 テスラバルブ内流れの指向性向上に及ぼす流路形状の検討(マイクロ・ナノスケールの熱流体現象(4))

Microvalves are the essential parts of valveless micropumps and other integrated microfiudic systems. The non moving parts (NMP) valve of which geometry is fixed is a simple and reliable valving concept. This paper proposes R type valve as the improved form of 'Tesla valve' which is one of the NMP valves, and evaluated its performance numerically. In the R type valve case, diodicity was 1.37 at Re = 500 and 14% more efficient than the optimized Tesla valve. In addition, the flow characteristics of pulsating flow in low Re regime was different from those of steady flow with the identical instantaneous Re conditions.