Linear Inflow Research Articles

Case series of genital lymphaticovenous anastomosis for genital lymphatic vesicles

BackgroundThe management of lymphatic vesicles is challenging. This study aimed to clarify the lymphatic flow around the genitals and the effect of genital LVA on genital lymphatic vesicles. MethodsWe performed a retrospective study of 34 patients who underwent resection for lymphatic vesicle and LVA. In patients with genital lymphedema, two types of lymphatic inflow existed around the genital area; from the lower extremities (type 1) and from the buttocks (type 2). Lymphoscintigraphy was performed to detect type 1 lymphatics injecting isotope into the first interdigital area. ICG lymphography was performed to detect type 2 lymphatics injecting ICG into the ischial tuberosity. We performed resection of lymphatic vesicles and LVA in the legs and/or in the genitals. Postoperative recurrence rate of lymphatic vesicles and the frequency of cellulitis were evaluated. ResultsType 1 lymphatics were observed in 38.2% of the patients. In ICG lymphography, there was linear inflow to the genitals in 40.9% and DB inflow in 24.2%. In 10 patients (29.4%), both type 1 and 2 lymphatic vessels were observed. Genital LVA was performed in 31 patients and lower extremity LVA was performed in 15 patients. The average follow-up period was 332 days, and recurrence was observed in 8 (25.8%) of 31 patients who underwent total resection. The average number of cellulitis episodes decreased significantly from 2.8 times before surgery to 0.31 times after surgery (p<0.01). ConclusionLVA in the genital area and lower limbs was effective in preventing postoperative recurrence of lymphatic vesicles after resection.

Modeling of a novel cascade-type electrocoagulation reactor using iron electrodes. Characterization of bubbling flow and coagulant dosage

This paper deals with the bubbling flow and coagulant dosage modeling in an innovative continuous cascade-type electrocoagulation (EC) reactor using iron plate electrodes. The reactor comprises seven iron plates. It is open to the atmosphere at the top to release the hydrogen bubbles produced at the cathode during the reduction of H2O. In this context, a two-phase flow model (H2OH2) was formulated. The H2OH2 flow was obtained by the solution of the Reynolds Averaged Navier-Stokes (RANS) equations for the continuous phase (H2O), which was coupled to the slip model for the dispersed phase (H2). Since H2 bubble formation co-occurs at the cathode as the aqueous solution passes through the continuous EC reactor, the two-phase flow and Laplace equations were solved simultaneously. The modeling of the ferric ion coming from the anodic dissolution was carried out by solving the diffusion-convection equation. The influence of the mean linear inflow velocity (2.63 ≤ u ≤ 2.56 cm s−1) and current density (4 ≤ j ≤ 8 mA cm−2) on the H2 dispersion and coagulant formation (Fe3+) was systematically examined. A comparison between simulated and experimental Fe3+ doses showed deviations < 4%. Excellent agreement between experimental and theoretical residence time distribution curves was obtained.

Computational Fluid Dynamic Analysis of Turbo Cyclone and Intake Manifold Spacer on Honda Supra Fit

The need for human mobility is constantly increasing over time, so the demand for vehicle production mass is still relatively high. A large number of conventional vehicle use makes the impact of dependence on fuel oil. This dependence is very threatening for various aspects. Increasing the combustion efficiency in the engine room is necessary. Turbo cyclone is an additional component applied to the intake manifold, which causes the originally linear inflow to rotate (swirl) and mix fuel with air more maximally in the combustion engine to increase the combustion efficiency. Recently, we fabricated and characterized turbo cyclone and intake manifold spacer to increase the combustion engine's performance. Turbo cyclone designed in two different blades with a degree 400 with an angle of inclination blade. Intake manifold spacer designed with 24 grooves with a 400 angle. A selected sample in this research is the Honda Supra Fit 125CC year 2006. In this study, to increase the combustion engine's performance, we applied the 3-blade turbo cyclone and 4-blade turbo cyclone in the air filter. We applied an intake manifold spacer between the combustion engine and carburetor. Computational Fluid Dynamic (CFD) of turbo cyclone and intake manifold spacer is shown the changing in velocity, pressure, and turbulence intensity. The specific result shown in 4-blade turbo cyclone with change in velocity is 0.14009 m/s, with pressure drop -0.04582 Pa, and the change of turbulence intensity value is 2.44536 % explain that the turbulence condition is a medium-turbulence case. The unspecific result in the intake manifold spacer shows only a change in velocity 0.26269 m/s with a pressure drop of only -0.00673 Pa, which means the inner flow profile is almost linear. It proves from turbulence intensity value only 0.41247 % explain that internal air-flow in low-turbulence flow condition. Based on turbulence case from turbulence intensity, it has shown increased performance in the medium-turbulence case. These results suggest that turbo cyclone and intake manifold spacer can increase the performance of combustion engines.

Real-time prediction framework for frequency-modulated multirotor noise

A comprehensive multirotor noise assessment framework is developed to predict the noise of rotational-speed-controlled rotor configurations in real-time. The key objectives are to synthesize the frequency-modulated multirotor noise and analyze the frequency modulation (FM) characteristics. The framework includes modules associated with the flight control, aerodynamics, time reconstruction, noise prediction, and time-frequency analysis (TFA). In addition to the hybrid blade element momentum model, the aerodynamics module contains a linear inflow model, a Beddoes wake model, and an unsteady aerodynamic correction model. The convective form and source-time dominant algorithms are used in the acoustic analogy for tonal noise prediction. The FM characteristics are identified using the synchrosqueezing-based high-resolution TFA for strongly non-stationary signals. The framework is verified through validation and verification studies for diverse rotor configurations and flight conditions. During the cruise flight of the multirotor, the tonal noise exhibits simultaneous frequency and amplitude modulations. In wind gust conditions, these modulations result from rotational speed variations, acoustic wave interference, and Doppler shifting. By clarifying the non-stationary noise signal in diverse flight environments, the proposed framework can facilitate noise assessment in the perception-influenced design stage of multirotor configurations.

Effects of rotor inflow models on dynamic responses of variable-pitch quadrotors

In this paper, effects of rotor inflow models on dynamic responses of variable-pitch quadrotors is investigated. The rotor inflow include both the static and dynamic inflow model formulated in first order form and fit quite into the formulation and solution methodology of the developed mathematical model. The main advantage of these models referred to computationally inexpensive and their particular form required to be coupled to the developed quadrotor model representing in the state space. Accordingly, the linear Drees model and Pitt-Peters dynamic inflow model are proposed to modify the quadrotor dynamic model and to capture the effects of rotor trailed wake provided unsteady properties for rotor aerodynamic model. This dynamic inflow is a three state model consists of uniform, sine, and cosine inflow components formulated based on rotor thrust, pitching, and rolling moments and it represents a linear radial distribution with first harmonic azimuthal distribution over the rotor disc. The linear and non-linear controllers are also designed for the variable-pitch quadrotor to improve the quality of dynamic responses. Furthermore, the non-linear controller, feedback linearization, guarantees the stability of the quadrotor in different maneuvers using the Lyapunov functions. The obtained results against experimental data show that the suggested inflow models can support the quadrotor dynamic responses with a higher resolution.

Analytical model of the linear inflow to a horizontal well with hydraulic fractures in low-permeability reservoirs

At present, increasing attention has been concentrated on low-permeability deposits whose development is tightly related with technologies of horizontal drilling and hydraulic fracturing of the reservoir. However, the simultaneous presence of a horizontal section of the well and hydraulic fractures in the reservoir impedes the process of flow of reservoir liquids and gases through the porous medium and complicates simulation of such flows. In the present study a new analytical model of the linear inflow to a horizontal well with hydraulic fractures in low-permeability reservoirs is proposed. This is a generalizing model which takes into account both situations when there exists a linear flow in the direction perpendicular to the borehole of a horizontal well in the distant sections of the reservoir and when there is a linear flow in the direction parallel to the borehole of a horizontal well. The use of the model is not restricted by the shape of the flow domain. The new model proposed has a wide application field and does not require complex computations.

A nonlinear, adaptive observer for gas-lift wells operating under slowly varying reservoir pressure

A nonlinear observer that estimates well flow rates and downhole pressure based on topside measurements only has been presented in the literature. As demonstrated in laboratory experiments the observer is suitable for a coupling with conventional PI control for stabilization of slug flow. The design of the observer is based on a nonlinear model with a linear inflow relation, and demands knowledge of several uncertain well parameters, including the reservoir pressure and production index. In this paper we present an adaptive extension to the nonlinear observer that eliminates one uncertain parameter by estimating the reservoir pressure. The extended observer is shown to be globally uniformly asymptotically stable and retain the properties of the original observer.

Aeroelastic Analysis of a Hingeless Rotor Using a Dynamic Wake Model

Aeroelastic Analysis of a Hingeless Rotor Using a Dynamic Wake Model

Bacterial-sized particle inflow through sutured clear corneal incisions in a laboratory human model

To determine the effectiveness of a single radial suture placement in 2 clear corneal incision (CCI) configurations in preventing inflow of bacterial-sized particles. Wilmer Eye Institute, Baltimore, Maryland, USA. Experimental study. Ten human globes were used. Two 25-gauge needles connected to a saline solution bag and to a digital manometer were inserted through the limbus 120 degrees apart. Four incision-suture combinations were evaluated sequentially in each cornea. All incisions had the same dimensions (2.75 mm width, 3.00 mm length). Two incisions were single plane, and 2 were biplane. One incision from each configuration was left unsutured, and the other was sutured (10-0 nylon). With a preset 10 mm Hg intraocular pressure (IOP), India ink was applied to the incision site and a sudden IOP fluctuation was induced. Inflow was outlined and measured by planimetry. There was a significant increase in area and linear distance of India-ink inflow after pressure challenge in all groups (P < .05), but with important differences among them. When the sutured and unsutured groups from each CCI were compared, there was a significantly smaller area of inflow in the 2-step unsutured group (P < .05). The linear inflow was higher in both sutured groups; however, the difference was significant for the 2-step incision configuration only (P < .05). A single radial suture reduced the area of inflow of bacterial-sized particles but increased the linear distance of inflow in single-plane 3.0 mm incisions. Suture placement in a stepped incision increased inflow of bacterial-sized particles. No author has a financial or proprietary interest in any material or method mentioned.

동적 유입류 모델을 이용한 회전익기 전진비행 공탄성 해석

본 논문에서는 비정상 공기력을 모델링하기위해 Peters-He의 동적유입류모델을 고려한 2차원 준정상 공기력 이론을 적용하여 회전익기 전진비행에 대한 공탄성 해석을 수행하였다. 또한, 공력탄성학적 안정성 해석을 수행하기 위하여, 전진비행 시 주기적인 특성을 갖는 비선형 정적 트림 해를 얻기 위해 동체 평형을 고려한 연계 트림 해석을 통한 완전 유한요소 방정식을 이용하였다. 동적유입류모델의 공력과 구조 특성을 검증하기 위해 유도 유입류와 깃끝에서의 구조변형을 타 수치해석결과와 비교하였다. 또한, 공탄성 안정성을 검증하기 위해 두 모델의 래그 감쇠값을 비교하였다. In this study, the aeroelastic analysis of rotorcraft in forward flight has been performed using dynamic inflow model to handle unsteady aerodynamics. The quasi-steady airload model based on the blade element method has been coupled with dynamic inflow model developed by Peters and He. The nonlinear steady response to periodic motion is obtained by integrating the full finite element equation in time through a coupled trim procedure with a vehicle trim for stability analysis. The aerodynamic and structural characteristics of dynamic inflow model are validated against other numerical analysis results by comparing induced inflow and blade tip deflections(flap, lag). In order to validate aeroelastic stability of dynamic inflow model, lag damping are also compared with those of linear inflow model.

Development of an Unsteady Aerodynamic Analysis Module for Rotor Comprehensive Analysis Code

The inherent aeromechanical complexity of a rotor system necessitated the comprehensive analysis code for helicopter rotor system. In the present study, an aerodynamic analysis module has been developed as a part of rotorcraft comprehensive program. Aerodynamic analysis module is largely classified into airload calculation routine and inflow analysis routine. For airload calculation, quasi-steady analysis model is employed based on the blade element method with the correction of unsteady aerodynamic effects. In order to take unsteady effects - body motion effects and dynamic stall - into account, aerodynamic coefficients are corrected by considering Leishman-Beddoes's unsteady model. Various inflow models and vortex wake models are implemented in the aerodynamic module to consider wake induced inflow. Specifically, linear inflow, dynamic inflow, prescribed wake and free wake model are integrated into the present module. The aerodynamic characteristics of each method are compared and validated against available experimental data such as Elliot's induced inflow distribution and sectional normal force coefficients of AH-1G. In order to validate unsteady aerodynamic model, 2-D unsteady model for NACA0012 airfoil is validated against aerodynamic coefficients of McAlister's experimental data.

회전익기 통합해석프로그램을 위한 공력해석코드 개발

본 논문에서는 회전익기 통합해석프로그램개발의 일환으로 공력해석코드를 개발 및 검증하였다. 기본적인 공력하중은 익형 공력테이블을 이용한 깃요소이론을 기반으로 계산하였고, 로터의 유도 유입류를 계산하기 위해 선형유입류 모델, 동적유입류 모델, 지정후류모델, 자유후류 모델 등 여러 유입류 예측기법을 사용하였다. 각 모델의 특성을 파악하기 위해 Elliott 등의 유도 유입류 실험결과와 AH-1G 실험결과의 국소 수직력계수를 비교 및 검증하였다. In this study, an aerodynamic performance analysis code has been developed as a part of rotorcraft comprehensive program. Airloads on rotor blades are calculated based on the blade element theory with look-up tables of aerodynamic coefficients of 2-D airfoils. In order to calculate rotor induced inflow, various inflow prediction methods such as linear inflow, dynamic inflow, prescribed wake and free wake model are integrated into the present module. The aerodynamic characteristics of each method are compared and validated against available experimental data such as Elliot's inflow distribution and sectional normal force coefficients of AH-1G.

전진비행하는 회전익기 로터의 평균 유입류 예측기법 연구

Prediction methods for a rotor averaged inflow in forward flight are investigated in this study. The investigated methods are Drees linear inflow model, Mangler & Squire model and free vortex wake(FVW) method. Predictions have been performed for a four-blade rotor operating at three different advance ratios i.e. 0.15, 0.23 and 0.30, at which experimental data are available. According to results, Drees model has a limitation for the inflow non-uniformity prediction due to an inherent linear characteristics. Mangler & Squire model has a reasonable accuracy except the disk edge region. KARI FVW method has very good accuracy and has better accuracy than the other FVW method especially in inboard region. However, there are some discrepancies in retreating side due to the dynamic stall effect and in near hub region due to the fuselage upwash effect.

Optimum Two-Per-Revolution Inputs for Improved Rotor Performance

The results of a study to determine the optimum two-per-revolution blade control inputs required to minimize rotor power, maximize thrust, or minimize rotor speed, using formal numerical optimization techniques, are presented. The impact of improved rotor modeling on the prediction of the effects of two-per-revolution input on rotor power is also addressed, in particular, the effect of using a free wake inflow model, and a flexible rotor blade model. The main conclusions of the present study are as follows: The optimization for optimum two-per-revolution input is best carried out by solving the trim problem for every value of the inputs proposed by the optimizer, as opposed to integrating the trim calculations as equality constraints in the optimization. An appropriate two-per-revolution input can increase the rotor maximum thrust at high speed by about 11%. The additional thrust is generated at the front and the rear of the rotor disk. The two-per-revolution input can also further reduce the rotor speed compared with a case without such input. The physical mechanism is the same as in the optimization for maximum thrust, and the maximum value of C T /σ is also the same. Although the power predictions obtained using a free wake model are different from those obtained with a simpler linear inflow model, the accuracy of the optimum two-per-revolution input predicted using the simpler model is adequate. The best practical strategy to optimize the two-per-revolution input is to conduct an initial study with a simple linear inflow model and then refine it with the more sophisticated one. The same conclusions hold for more sophisticated flexible blade models, compared with simpler rigid blade ones.