Computational Study on Noise of Urban Air Mobility Quadrotor Aircraft

2021 ◽  
Author(s):  
Zhongqi (Henry) Jia ◽  
Seongkyu Lee
Keyword(s):  
Sound Pressure ◽  
Computational Study ◽  
Urban Air ◽  
Noise Levels ◽  
Cfd Simulations ◽  
Community Noise ◽  
Cfd Models ◽  
Quadrotor Aircraft ◽  
Computational Fluid Dynamics Cfd ◽  
The One

This paper investigates the acoustics of a one-passenger and a six-passenger quadrotor urban air mobility (UAM) aircraft in level flight based on a high-fidelity computational fluid dynamics (CFD) approach. The CFD simulations are carried out using the HPCMP CREATETM-AV multidisciplinary rotorcraft analysis and simulation tool Helios. The acoustic simulations are performed using the acoustic prediction tool PSU-WOPWOP. A total of three CFD models are simulated: a one-passenger isolated rotor configuration, a one-passenger full configuration with a fuselage, and a six-passenger isolated rotor configuration. The noise comparison between the one-passenger isolated rotor case and the full configuration case shows that the vehicle fuselage increases the A-weighted sound pressure level (SPL) up to 5 dB. The acoustic comparison between the one-passenger and the six-passenger isolated rotor configuration shows that the maximum overall SPL difference is up to 14 dB. Furthermore, it is shown that the noise of the six-passenger configuration is approximately 11 dB lower than that of a similar-sized conventional helicopter in an overhead scenario. The community noise impact of UAM aircraft is also assessed and compared to various background noise levels. The results show that the one-passenger quadrotor noise can be fully masked by freeway noise at an altitude greater than or equal to 1000 ft, while the six-passenger quadrotor noise can only be partially masked by freeway noise even at an altitude of 1000 ft.

Computational Study of the Downpull Force on High-Head Slide Gates

2019 ◽  
Author(s):  
Juan C. Arango Escobar ◽  
David Calderon Villegas ◽  
Aldo Benavides Moran ◽  
Alejandro Molina Ochoa
Keyword(s):  
Computational Study ◽  
Maximum Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Flow Through ◽  
High Head ◽  
The One ◽  
Bottom Outlet

Abstract This paper presents CFD simulations of the flow through a real bottom outlet equipped with high-head slide gates. The operating head of the gates and the maximum flow rate are 70 m and 650 m3/s, respectively. The numerical simulations were performed in ANSYS-FLUENT version 19.2. VOF method was used to model the free surface flow downstream the slide gates. Hydrodynamic forces were calculated at nine gate openings for a standard 45° lip gate; the downpull coefficients obtained from the simulations were compared with estimates from Naudascher’s analytical method. According to the CFD results, the downpull force acting on the 45° lip gate is 5%–10% lower than the one estimated analytically for the analyzed gate positions. Additionally, the flow through an inverted 30° lip gate was simulated to estimate the downpull coefficient at various gate openings. These coefficients cannot be determined analytically. The methodology here described can easily be applied to different gate geometries for which design coefficients are not available.

scholarly journals CFD Models as a Tool to Analyze the Performance of the Hydraulic Agitation System of an Air-Assisted Sprayer

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 769 ◽  
Author(s):  
Jorge Badules ◽  
Mariano Vidal ◽  
Antonio Boné ◽  
Emilio Gil ◽  
F. Javier García-Ramos
Keyword(s):  
Fluid Velocity ◽  
Water Levels ◽  
Correct Prediction ◽  
Cfd Simulations ◽  
Cfd Models ◽  
Fluid Velocities ◽  
Computational Fluid Dynamics Cfd ◽  
Relative Errors ◽  
Setting Parameters ◽  
System Water

A computational fluid dynamics (CFD) model of the fluid velocities generated by the agitation system of an air-assisted sprayer was developed and validated by practical experiments in a laboratory. The model was developed considering different settings of the agitation system: Three water levels in the tank (1000, 2000, and 3000 L); two different numbers of active nozzles (2 or 4); and three working pressures of the agitation circuit (8, 10, or 12 bar). Actual measurements of the fluid velocity into the tank were taken using an acoustic Doppler velocimeter (ADV). CFD simulations made it possible to estimate fluid velocities at 38% of the measuring points with relative errors of less than 30%. Additionally, the CFD models have allowed the correct prediction of the general behavior of the fluid in the tank considering mean velocities depending on the setting parameters of the agitation system (water level in the tank, hydraulic circuit pressure, and number of active nozzles).

Computational Study of Multiple Hydrokinetic Turbines: The Effect of Wake

2015 ◽  
Author(s):  
Cosan Daskiran ◽  
Jacob Riglin ◽  
Alparslan Oztekin
Keyword(s):  
Computational Study ◽  
Relative Power ◽  
Cfd Simulations ◽  
Significant Drop ◽  
Hydrokinetic Turbines ◽  
Hydrokinetic Turbine ◽  
Wake Interactions ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design

Computational Fluid Dynamics (CFD) simulations have been conducted to investigate the performance of a predetermined propeller-based hydrokinetic turbine design in staggered and non-staggered placements for river applications. Actual turbine models were used instead of low fidelity actuator line or actuator disks for CFD simulations to achieve more reliable results. The k-ω Shear Stress Transport (SST) turbulence model was employed to resolve wall effects on turbine surface and to determine wake interactions behind the turbines. The wake interaction behind the upstream turbine causes significant drop on downstream turbine performance within non-staggered configuration. The upstream turbines in both staggered and non-staggered placement offers the same relative power of 0.96, while the relative power for downstream turbine is 0.98 for staggered installment and 0.16 for inline placement.

scholarly journals Computational Fluid Dynamics Modeling of Liver Radioembolization: A Review

2021 ◽  
Author(s):  
Jorge Aramburu ◽  
Raúl Antón ◽  
Macarena Rodríguez-Fraile ◽  
Bruno Sangro ◽  
José Ignacio Bilbao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Point Of View ◽  
Cfd Modeling ◽  
Dynamics Modeling ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Modeling ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Intraarterial Therapy

AbstractYttrium-90 radioembolization (RE) is a widely used transcatheter intraarterial therapy for patients with unresectable liver cancer. In the last decade, computer simulations of hepatic artery hemodynamics during RE have been performed with the aim of better understanding and improving the therapy. In this review, we introduce the concept of computational fluid dynamics (CFD) modeling with a clinical perspective and we review the CFD models used to study RE from the fluid mechanics point of view. Finally, we show what CFD simulations have taught us about the hemodynamics during RE, the current capabilities of CFD simulations of RE, and we suggest some future perspectives.

Air-Side Performance Characterization of Air-to-Refrigerant Heat Exchangers Using Parallel Parameterized CFD

2013 ◽  
Author(s):  
Khaled Saleh ◽  
Weizhe Han ◽  
Vikrant Aute ◽  
Reinhard Radermacher
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Cfd Simulations ◽  
Cfd Models ◽  
F Factor ◽  
Wide Range ◽  
Different Types ◽  
Computational Fluid Dynamics Cfd ◽  
Friction Performance

The goal of the study presented in this paper is to use Computational Fluid Dynamics (CFD) to characterize the heat transfer and friction performance of fins used in air-to-refrigerant heat exchangers. Five different types of fins used in air-cooled heat exchangers (HXs) are studied using Parallel Parameterized CFD (PPCFD) approach described in this paper. The fin types considered in this paper are; Plain, Wavy, Slit, Super Slit, and Louver. 3-D CFD models are built and tested for these fin types. Based on the CFD results, air side heat transfer coefficient (HTC), Colburn j factor, Fanning f factor, and pressure drop are calculated. The results from CFD simulations are compared against experimental data from the literature for the different fin types and a good agreement is found between the two. In addition, the results from CFD simulations are used to evaluate the thermal and hydraulic performance for a wide range of heat exchanger parameters such as tube diameters, fin pitch, number of rows, and frontal air velocity. The results show the advantages of using PPCFD to efficiently develop correlations for different types of fins used in air-cooled HX, with significant reduction in engineering time. The PPCFD approach can be extended to efficiently optimize novel heat transfer surfaces.

scholarly journals Hydrodynamic Evaluation of Five Influent Distribution Systems in a Cylindrical UASB Reactor Using CFD Simulations

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3141
Author(s):  
Juan F. Cisneros ◽  
Fabiola Cobos ◽  
Manuel Raul Pelaez-Samaniego ◽  
Usman Rehman ◽  
Ingmar Nopens ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Distribution System ◽  
Distribution Systems ◽  
Uasb Reactor ◽  
The Novel ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Hydrodynamic Evaluation ◽  
The One ◽  
Uasb Reactors

UASB reactors are a promising option for environmentally friendly wastewater treatment due to their reduced carbon footprint and their capacity to treat a variety of wastewater strengths, among other recognized advantages over alternative wastewater treatment systems. The Influent Distribution System (IDS) is a critical structure for generating granules in a UASB reactor since it provides the required flow hydrodynamics for their formation. Thus, the objective of this study was to evaluate and compare the efficiency of five IDS configurations to generate ideal granulation conditions using Computational Fluid Dynamics (CFD) simulations. The IDS configurations were as follows: (C1) single radial inflow, (C2) upward axial inflow, (C3) downward distributed axial inflow, and two novel configurations in the form of (C4) double opposite radial inflow and (C5) downward tangential inflow. The hydrodynamic response of configuration C1 was validated in a physical model with dynamic Froude similitude. The granulation measurement was velocity-based in the reactor reaction zone using steady-state CFD simulations. The novel IDS configuration C4 was the one that resulted in the highest granulation volume, with up to 45.5% of the potential granulation volume of the UASB reactor, in contrast to the IDS C2 that obtained the lowest granulation with only 10.8%. Results confirm that the IDS directly impacts the hydrodynamics of the reactor and that model-based design can be used to ascertain IDS configurations that better promote granulation in UASB reactors.

Computational Study of Viscoelastic Flows in Microchannels

2021 ◽  
Author(s):  
Guanyang Xue ◽  
Xuanhong Cheng ◽  
Alparslan Oztekin
Keyword(s):  
Numerical Study ◽  
Computational Study ◽  
Viscoelastic Flows ◽  
Computational Domain ◽  
Cfd Simulations ◽  
First Normal Stress Difference ◽  
Computational Fluid Dynamics Cfd ◽  
Convergence Study ◽  
Cell Densities ◽  
Mesh Convergence

Abstract Computational Fluid Dynamics (CFD) simulations have been performed in a 2D cross-section of the microchannel to characterize the viscoelastic flow field using OpenFOAM with customized stabilizing methods. The continuity and momentum equations coupled with the Giesekus constitutive model are solved. The computational domain consists of a straight main channel that is 100 μm in width and a 1:4 square-shaped cavity in the middle of the channel. The mesh convergence study is performed with both structured and unstructured cells. Flow and stress fields are compared with different cell densities. The numerical study is carried out on various Deborah numbers (De). The first normal stress difference is computed to examine the elastic lift force for future studies for nanoparticle separations. The vortex on the expansion side shrinks while the contraction side expands as De is increased. A banded zone of stronger N1 in the bulk region of the cavity, observed at higher De, could be favorable in particle separation applications. As the simulation process being validated, this study can help with future improvements to achieve higher flow rates.

scholarly journals Using CFD to Evaluate Natural Ventilation through a 3D Parametric Modeling Approach

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2197
Author(s):  
Nayara Rodrigues Marques Sakiyama ◽  
Jurgen Frick ◽  
Timea Bejat ◽  
Harald Garrecht
Keyword(s):  
Natural Ventilation ◽  
Parametric Modeling ◽  
Cfd Simulations ◽  
3D Design ◽  
Post Process ◽  
Test House ◽  
Model Set ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Passive Strategy

Predicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

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