Unsteady Numerical Simulations Research Articles

Cavitation mitigation via curvilinear barriers in centrifugal pump

Cavitation is a significant problem in hydraulic machinery that leads to the deterioration of hydraulic performance, material damage, and flow instability. While current methods partially address cavitation instability, there is a lack of comprehensive understanding of the control mechanisms. This study focuses on controlling cavitation flow instability in a centrifugal pump by proposing an active method using obstacles on the blade's surface. A low-specific speed centrifugal pump was chosen as the research object, and a three-dimensional unsteady full-flow channel numerical simulation was conducted. The findings indicate that in the absence of cavitation, the wake vortex induced by obstacles increases energy loss in the centrifugal pump, resulting in a slight drop in efficiency. However, when cavitation occurs, the obstacles effectively improve the flow field, reduce the vortex strength near the back of the blade in the flow channel, and significantly reduce the growth rate of cavitation volume. This reduction is observed in both the cavitation volume and its first derivative. Thus, the obstacles optimize the flow structure, reduce vortex strength, and slow the growth rate of cavitation. The main control mechanism involves inducing high-pressure waves to collapse cavities and improving flow transition characteristics. To solve the inverse problem of cavitation control with obstacles inside a centrifugal pump, dimensionless geometric parameters are studied to determine better suppression effects.

Numerical study on the influence of the bucket offset angle on the flow field of Pelton turbines with six-nozzles

Abstract Pelton turbines are emerging as a primary means for exploiting ultra-high water head resources. The hydraulic performance of a Pelton turbine is determined by the design of its runner/bucket. Among the critical parameters that affect the hydraulic performance of multi-nozzle Pelton turbines is the bucket offset angle (α). To investigate the influence of bucket offset angle on the flow field of Pelton turbines with six nozzles, this study conducted unsteady numerical simulations of gas-liquid two-phase flow for various bucket offset angles, employing the VOF multiphase model combined with the SST k-ω turbulence model. The results reveal that as the bucket offset angle increases, the axial width of the water sheet formed by the current jet progressively widens, with a tendency to catch up with the water film formed by the previous jet during the torque rising stage. Moreover, the increased bucket offset angle causes the water sheet to distribute more closely to the bucket cutout, raising the risk of leakage from the cutout. Notably, at α= 10°, some of the water sheet has already flowed out of the cutout and collided with the subsequent jet.

Study of the Effect of Incoming Flow with Fluctuating Gas Void Fraction on Transient Characteristics of a Three-stage Multiphase Pump

Abstract For the oil field with high gas content, the oil well produced has obvious gas content fluctuation characteristics. The unsteady flow of multiphase pump will be caused by the fluctuation flow into the pump. In this paper, the unsteady numerical simulation of the flow field in a three-stage multiphase pump is carried out by using Euler-Euler two-fluid model and SST turbulence model. The results show that the pressurization and torque of each impeller change with the fluctuation of the inlet gas content. The second stage impeller has the highest fluctuation due to the change of flow pattern. The inlet gas rate pulsation frequency and static and static interference have significant effects on the pressure pulsation in the impeller, and the dominant frequency is gas rate pulsation frequency or 11 times rotation frequency. The dominant frequency of the diffuser is the blade passing frequency and its double frequency, and the pulsation frequency of the gas content is the secondary frequency and the amplitude is relatively stable. The axial force increases with the increase of gas content, while the radial force changes in reverse.

Effect of inlet distortion on internal flow and performance of a contra-rotating fan operating with single-stage impeller

To establish a theoretical foundation for the rational selection of contra-rotating fans operating with a single-stage impeller under inlet distortion. Unsteady numerical simulations were conducted using the SST k-ω turbulence model to analyze the airflow fields, respectively, for the single-stage operation of front impeller (SSOFI) and the single-stage operation of rear impeller (SSORI) of the fan. The internal flow characteristics with single-stage operation under both distorted inlet condition (DIC) and uniform inlet condition (UIC) were studied. Furthermore, a comparison of the performance parameters of the fan, including total pressure and total pressure efficiency, was conducted. Focusing on the SSOFI with satisfactory operational performance of the contra-rotating fan, this study aims to reveal the propagation of inlet distortion inside the fan and reveal the influence mechanisms of inlet distortions on the performance of the fan. The results indicate that the impact of inlet distortion on the flow field is primarily concentrated in the upstream area of the front-stage impeller for SSOFI. However, the flow disturbance from the exit of the front-stage impeller to the diffuser is relatively minimal. For SSORI, the inlet distortion exacerbates the adverse effect of the front stage impeller as the front guide vane on the flow inside the rear stage impeller. The entropy loss in the two-stage impellers is significantly higher than that under the uniform inlet condition, and the turbulence level in the diffuser is intensified. While the efficiency of the fan is significantly influenced by the inlet condition and operating stages, their impact on the total pressure is small. Specifically, under uniform inlet conditions, the total pressure efficiency for SSOFI exceeds that of SSORI by 4.9 %, whereas the difference rises to 11 % under inlet distortion condition.

Numerical Simulation and Experimental Study on the Aerodynamics of Propulsive Wing for a Novel Electric Vertical Take-Off and Landing Aircraft

The electric vertical take-off and landing (eVTOL) aircraft offers the advantages of vertical take-off and landing, environmental cleanliness, and automated control, making it a crucial component of future urban air traffic. As competition intensifies, demands for aircraft performance are escalating, including forward flight speed and payload capacity. The article presents a novel eVTOL design with propulsive wings and establishes methodologies for propulsive wing unsteady numerical simulation and wind tunnel experiments, analyzing its aerodynamic characteristics and lift enhancement mechanism. The results indicate that the cross-flow fan (CFF) provides unique airflow control capabilities, enabling the propulsive wing to achieve remarkably high lift coefficients (exceeding 7.6 in experiments) and propulsion coefficients (exceeding 7.1 in experiments) at extreme angles of attack (30°~40°) and low airspeeds. On the one hand, the CFF effectively controls boundary layer flow, delaying airflow separation at high angles of attack; on the other hand, the rotation of the CFF induces two eccentric vortices, generating vortex-induced lift and propulsion. The aerodynamic performance of the propulsive wing depends on the advance ratio and angle of attack. Typically, both lift and propulsion coefficients increase with the advance ratio, while lift and drag coefficients increase with the angle of attack. The propulsive wing shows significant advantages and prospects for eVTOL aircrafts in the low flight velocity range (0–30 m/s).

Mechanism analysis of the vortex ring and its effects on an axial descending rotor

A vortex ring is a flow phenomenon involving a complex toroidal vortex system. When a rotor is in descending flight, it may enter the vortex ring state (VRS), which will affect the rotor’s aerodynamic characteristics and even endanger it. In this paper, to clarify the aerodynamic mechanism by which the vortex ring exerts its effects on an axial descending rotor, an unsteady numerical simulation method for the rotor integrated with structured moving overset grids is proposed and validated using experimental data. This numerical simulation method is then applied to analyze the aerodynamic characteristics of the rotor in descending flight. The variations of the aerodynamic forces and the flow characteristics in the slipstream are analyzed to elucidate the physical mechanisms responsible for the relationships between the aerodynamic loads, flow field, and vortices when the rotor is in the VRS. The effects of the VRS cause a sharp drop in the average aerodynamic forces, which directly affects the safety and reliability of a rotor aircraft. In the slipstream of the descending rotor, a distinct vortex ring forms and moves upward as the velocity of descent increases. The most severe VRS occurs at a nondimensional velocity of descent of 1.13 when the center of the highly unsteady vortex ring is right at the blade tip, and this can be used as an indicator of the VRS. The physical mechanism by which the VRS exerts its effects can be attributed to the low pressure induced by strong vortices. The VRS decreases the pressure on the lower surface of the blade and increases the pressure on the upper surface, resulting in a reduction in the aerodynamic loads. In comparison with the hovering state, the VRS results in a much larger vortex strength and possesses a different vortex structure.

Influence of a Long Flexible Fiber on the Transport Capability of a Non-Clogging Pump

During the operation of non-clogging pumps, the flexible long fiber is prone to clogging and winding during the flow process, which can result in damage to the non-clogging pump, so a numerical simulation method of a solid–liquid two-phase flow in a non-clogging pump with a flexible long fiber is proposed in this paper. The unsteady numerical simulation of the two-phase flow of a single flexible fiber with different densities, lengths and diameters in a double-blade non-clogging pump was carried out to study the influence of fiber parameters on fiber transport capability. The results show that at a density of 920 kg/m3, 300 kg/m3 and 732 kg/m3, the transport capability of flexible fibers decreases successively, and the transport time T0 is 0.32 s, 0.36 s and 0.48 s, respectively. The transport capability of flexible fibers with a length of 150 mm, 200 mm and 250 mm decreases successively, and the transport time T0 is 0.34 s, 0.48 s and 0.96 s, respectively. The transport time T0 is 0.48 s when the fiber diameter dp is 5 mm. When the fiber diameter dp is 7.5 mm, the transport time T0 is 0.51 s. When the fiber diameter dp is 10 mm, the fiber transport capability of the non-clogging pump decreased significantly, and the transport time T0 is 0.68 s. The fiber length has the most obvious effect on fiber transport capability, followed by the fiber diameter and fiber density.

Study on the influence of variable inlet guide vane slot on the aerodynamic performance in air storage centrifugal compressor

The influence of variable inlet guide vanes with slots (SVIGVs) on the aerodynamic performance of an air-storage centrifugal compressor was studied using numerical simulations. The inlet position of the slot was set to 4 % of the chord length of the variable inlet guide vanes (VIGVs), and the outlet position was set to 14 %. The results show that the high-loss area near the VIGVs suction surface increases owing to the secondary flow generated by the slot jet, and the change in the inlet flow angle of the impeller results in a decrease in the compressor efficiency under the 30° pre-swirling angle condition. In contrast, the slot can effectively reduce the loss caused by the VIGVs at 40° and 50° pre-swirling angles and optimise the impeller inlet flow angle, thereby improving the efficiency and pressure ratio of the centrifugal compressor. At a pre-swirling angle of 50°, the efficiency and pressure ratio of the compressor increased by 8.3 % and 0.2, respectively. Furthermore, the influence of the SVIGVs on the impeller aerodynamic loads of a centrifugal compressor was revealed through an unsteady numerical simulation. The results showed that the SVIGVs effectively improved the aerodynamic load distribution on the impeller, reduced the aerodynamic load by three, four, and five times the frequency of rotation, and reduced the frequency amplitude by up to 2/3.

Numerical study on dynamic flow of flexible extension nozzle in rocket motors

The use of extension nozzles in rocket propulsion systems is one of the effective methods to increase the geometric expansion ratio and thrust of the nozzle. As a new type of extension nozzle, the flexible extension nozzle can achieve continuous changes in nozzle expansion ratio. To explore the characteristics of the flow field structure at the “bulge” structure and the step structure in the actual configuration of the flexible extension nozzle, and the impact on the performance of the nozzle, a three-dimensional numerical simulation model of the flexible extension nozzle was first established to study the flow field at the “bulge” structure, and then a two-dimensional unsteady numerical simulation model was established by using the coupling technology of dynamic grid and overlapping grid to study the flow field at the step structure. The results show that during the unfolding of the nozzle surface, a complex flow structure of “expansion fan-mixing layer-shock-vortex” were formed in the step area at the junction of the fixed section and the moving extension section. The specific impulse loss of the 3D model is larger than that of the 2D model due to the consideration of the “bulge” structure. The flow loss of the “bulge” structure and the step structure to the nozzle is 0.73% and 0.65% respectively.

Numerical simulation study on noise pollution of the pressurized gas system in pumped storage power station

To Investigate the noise pollution caused by pneumatic whistling during the blowdown operation of a pressurized gas storage system in a pumped storage power station, the flow field and sound field distribution of the gas storage tank under blowdown operation are analyzed in detail through full-channel unsteady numerical simulation of the gas storage tank and its supporting facilities. Subsequently, a comprehensive analysis of the noise issue in the gas cylinder was conducted. While investigating the mechanism of noise generation based on the distribution of noise intensity, the precise location of the noise source was pinpointed, providing a reference for the stability research of the exhaust pressurized water system.

Enhancement of aerodynamic performance of Savonius wind turbine with airfoil-shaped blade for the urban application

The present study introduces a novel rotor configuration with an airfoil-shaped blade, based on the low-speed high-lift FX74-CL5-140 airfoil, for enhancing the performance of the Savonius wind turbine for a practical application in urban areas. The preferment of the present design over the original one with a semicircular shape is confirmed by the sequence of unsteady two-dimensional (2D) numerical simulation. The results demonstrate a new power coefficient peak (up to 16.5 % better than that of the original rotor) could be gained at the tip speed ratio (TSR) of 1.1. The effective working range is further extended to TSR > 0.7 compared to that at TSR > 1.0 in the literature. Insight into the flow dynamic, including pressure, velocity, streamline, and wake analysis, reveals that the thick blade near the overlap region, benefiting in terms of the turbine’s high performance. The airfoil blade increases the momentum energy around the rotor, changes the pressure on the concave side, and varies the origin of the pressure force, leading to an increase in the moment arm with more torque exhibited on the rotor at high TSR. In addition, the proper orthogonal decomposition (POD) analysis is also performed to better understand the flow phenomena behind the rotor. Overall, the present design is beneficial for urban applications because it can enhance the rotor performance without losing the omnidirectional and compactness features.

Investigation of the Internal Flow Characteristics of a Tiltrotor Aircraft Engine Inlet in a Gust Environment

In the vertical take-off and landing (VTOL) state of tiltrotor aircraft, the inlet entrance encounters the incoming airflow at a 90° attack angle, resulting in highly complex internal flow characteristics that are extremely susceptible to gusts. Meanwhile, the flow quality at the inlet exit directly affects the performance of the aircraft’s engine. This work made use of an unsteady numerical simulation method based on sliding meshes to investigate the internal flow characteristics of the inlet during the hover state of a typical tiltrotor aircraft and the effects of head-on gusts on the inlet’s aerodynamic characteristics. The results show that during the hover state, the tiltrotor aircraft inlet features three pairs of transverse vortices and one streamwise vortex at the aerodynamic interface plane (AIP). The transverse vortices generated due to the rotational motion of the air have the largest scale and exert the strongest influence on the inlet’s performance, which is characterized by pronounced unsteady features. Additionally, strong unsteady characteristics are present within the inlet. Head-on gusts mainly affect the mechanical energy and non-uniformity of the air sucked into the inlet by influencing the direction of the rotor’s induced slipstream, thereby impacting the performance of the inlet. The larger head-on gusts have beneficial effects on the performance of the inlet. When the gust velocity reaches 12 m/s, there is a 1.01% increase in the total pressure recovery (σ) of the inlet, a 25.72% decrease in the circumferential distortion index (DC60), and a reduction of 62.84% in the area where the swirl angle |α| exceeds 15°. Conversely, when the gust velocity of head-on gusts reaches 12 m/s in the opposite direction, the inlet’s total pressure recovery decreases by 1.13%, the circumferential distortion index increases by 14.57%, and the area where the swirl angle exceeds 15° increases by 69.59%, adversely affecting the performance of the inlet. Additionally, the presence of gusts alters the unsteady characteristics within the inlet.

Axial Compressor Transonic Rotor Shock Interaction With Upstream Stator Row

Abstract Modern multistage axial compressors are designed for high aerodynamic loading and wide range with front stages rotor inlet relative Mach number above one over a large portion of span. Rotor shock waves propagate and reflect in the upstream stator where they provoke extra aerodynamic losses and aeromechanic risks. This paper discusses stator–rotor shock interactions using both steady and unsteady numerical simulations. The computations focus on three different stage designs with the same capacity and total pressure ratio, but different axial gaps and load distribution in stator and rotor. Speedlines from steady and unsteady computations compare the designs, and the detailed flow fields are analyzed at design and close to stall conditions. The steady and unsteady calculations predict similar stage performance, but different stator–rotor loss split. The analyses reveal how the rotor shocks orientation with respect to the upstream stator camber line controls the intensity of shocks interaction with the stator row and its propagation upstream. Finally, the paper indicates the ways to reduce the shock-driven rotor–stator interaction and suggests simple criteria to determine when to switch from steady to unsteady calculations for a reliable transonic stage performance prediction.

Numerical Research on Flow Characteristics at High Radii of Rim Seals with Different Geometric Structures

In the high-temperature mainstream of gas turbines, there is a rim clearance between the rotor and the stator. A rim seal is to prevent the intrusion of high-temperature gas by spraying cool fluid from the inside of the rim clearance to the outside. In the past research on rim seals, the focus was on the overall performance of the sealing structure, and the flow in the disc cavity was studied more, but the high-radius flow was simplified. In recent years, additional research in the field has focused on more complex sealing structures and high-radius flows, such as the interface between the disk cavity and the mainstream. There is more work to be conducted in this area of research. In this paper, the unsteady numerical simulation of the flow in four different rim sealing geometries is carried out by the URANS method. The flow phenomena and the influence of geometry on the flow are studied. The numerical simulation results are validated with the experimental results. It is found that the fluid in the rim sealing obviously presents two distinct forms and confrontations according to the tangential velocity. The flow in the sealing structure presents obvious circumferential non-uniformity. Compared with the single-axial structure, in the single-radial structure, the mixing area is induced by the radial geometry, and more vortex structures are generated, the mixing process is more intense, and the sealing effect is better. In the double-sealing structure, the inner structure plays the role of a barrier, and the cavity geometry between the two layers has a major influence on the sealing performance.

Research on pressure pulsation characteristics of a pump-turbine in pump mode with rotating stall: Focus on the broadband frequency

To investigate the adverse effects of rotating stalls on the pressure pulsation characteristics of a pump-turbine in pump mode, an unsteady numerical simulation was carried out by applying the partially averaged Navier–Stokes turbulence model. The numerical methods were carefully verified, and the onset flow rate of the hump at the performance curve and heads were in good agreement with the experimental data. The rotating stall appeared in the guide vane when the flow rate ranged from 0.514 to 0.887 times the best efficiency point (QBEP), with a frequency of 11.7% times the rotational frequency. In the period of a rotating stall, a sudden intensive pressure pulsation in the guide vane channel was observed and named as the component of the broadband frequency, and its corresponding flow mechanism was explained as the vortex evolution between the adjacent guide vane blades based on the dynamic mode decomposition technology. There were three distinct characteristics of broadband frequency: (i) intermittent occurrence when the rotating stall cell propagated to the current flow channel, (ii) a wide range of the frequency varying with flow rate, (iii) a considerable amplitude, e.g., reaching 21.1%–42.2% times that of the rotating stall frequency. In addition, both the frequency range and amplitude of the broadband frequency gradually decreased as the flow rate increased to 0.887QBEP. This study clarified the internal flow mechanism and frequency behaviors of a sudden intensive pressure pulsation if a rotating stall occurred, which was important to assess the stability of pump-turbine units.

Dynamic characteristics and application of dual throat fluidic thrust vectoring nozzle

Thrust vectoring technology plays an important role in improving the maneuverability of aircraft. In order to overcome the disadvantages of mechanical thrust vectoring nozzles, such as complications of structure and significant increases in weight and cost, fluidic thrust vectoring nozzles are proposed. Dual Throat fluidic thrust vectoring Nozzle (DTN) has received wide attention due to its excellent thrust vectoring efficiency and minimal thrust loss. In this study, three-dimensional unsteady numerical simulations of a single axisymmetric DTN are conducted first to analyze its dynamic response. Then the pitch and yaw control characteristics of DTN equipped on a flying-wing aircraft are investigated. It is found that the dynamic response will experience three stages: rapid-deflecting stage, oscillating stage, and steady stage. A complete recirculation zone forms at the end of the rapid-deflecting stage, which pushes the primary flow to attach to the wall opposite the secondary injection. Meanwhile, the exhaust flow is deflected. In terms of DTN’s application, the DTN equipped on the flying-wing aircraft is capable of providing effective pitch and yaw moments at all angles of attack and Mach numbers. In addition, continuous pitch and yaw moments can be obtained by adjusting the secondary mass flow ratios. The control moment is generated due to the asymmetrical pressure distribution of nozzle surface, which is mainly contributed by the pressure decrease on the secondary injection surface. Moreover, the DTN equipped on the flying-wing aircraft has a relatively high thrust vectoring efficiency of around 5°/% and a thrust coefficient of around 0.95 when nozzle pressure ratio equals 4. These results provide an important theoretical basis for the practical application of DTN.

Dynamic risk evaluation of supersaturated dissolved gas at a confluence with unsteady flow conditions

The confluence of two rivers gives rise to a distinctive hydrodynamic structure where numerous nutrients can be accumulated, making the confluence area a pivotal biological habitat. The threat of supersaturated dissolved gas in upstream water caused by dam discharging is indispensable for the confluence areas. Therefore, it is imperative to study and assess the risks faced by fish in these areas, particularly when the merging of main and tributary streams leads to varying degrees of supersaturation and non-uniform distribution of dissolved gases. The spatial and temporal distribution of supersaturated dissolved gas at the natural confluence in the Yangtze River utilizing continuous prototype monitoring and unsteady flow numerical simulation was investigated, and a dynamic evaluation method that classifies risk into three levels (high, medium, low) was proposed. The confluence area exhibited evident non-uniform distribution characteristics, wherein the primary factors influencing this distribution were identified as the dissolved gas saturation of inlet flow, and flow ratio. The presence of non-continuous discharge intensity resulted in an increase in medium-risk areas within the river, thereby mitigating the risk to fish from the supersaturation of the discharge. A velocity barrier was formed at the confluence, with the velocity range being 1.8 ∼ 3.4 m/s, exceeding the fish’s burst speed of 1.7 m/s. Because of the barrier, there was no direct access to the low-saturation areas, and potential avoidance routes are primarily located in the medium-risk zones downstream. The paper offers a useful method to assess risk distribution in critical ecological regions characterized by non-constant characteristics. Additionally, it recommends dam discharging strategies to expand the scope of fish risk avoidance.

Optimization and experimental study of stationary endwall of stator labyrinth cavity in a low-speed research compressor

Controlling the leakage flow of the labyrinth seal cavity is very important for the efficiency and aerodynamic matching design of aero-engine high-pressure compressor. However, due to the complexity of the geometry and internal flow of the labyrinth seal cavity, the design optimization of the labyrinth seal cavity is rarely studied. In this paper, a multi-objective design optimization method was used to optimize the stationary endwall of the shrouded stator labyrinth cavity, and the optimal endwall shape was obtained. Based on the optimal geometry, the 3D printing and aerodynamic testing of experimental parts were carried out, and the aerodynamic performance and flow field details of the optimal geometry were analyzed by unsteady numerical simulation. The experimental results show that for the optimal geometry, it has a little effect on the total pressure ratio, but the efficiency at the design point is increased by 1.4 %. The numerical results show that the optimal cavity shape reduces low-energy fluid, thus reduces the total pressure loss of S3. At the near stall point, the optimal S3 still has a better performance, which means that the optimal shape is not limited to the design point. From the result, an engineering design criterion can be concluded. It is suggested that the labyrinth seal cavity should be designed to match the velocity components of the leakage flow with the mainstream of the stator properly to make the leakage flow go evenly in the blade passage instead of gathering to the suction side.

Unsteady internal flow characteristics study of a hydrogen circulation pump under different pressure differential conditions

The purpose of this paper is to investigate the flow and pressure pulsation characteristics of hydrogen circulation pump under varying pressure differences. A dynamic mesh technology was employed to conduct an unsteady numerical simulation of the interior of the hydrogen pump. The pressure pulsation within the pump cavity area was analyzed using fast Fourier transform, and the unevenness of pressure and flow inside the pump under varying pressure differential conditions was specifically studied. The results reveal that interference between dynamic and static in the pump cavity, caused by meshing clearance between rotors and radial clearance between the rotor and pump cavity, leads to pressure pulsation peaks occurring at twice the rotational frequency at all monitoring points. Additionally, as the pressure difference increases, the exhaust flow rate at the outlet of the pump cavity decreases from 49.237 m3/h to 12.392 m3/h, while volumetric efficiency decreases from 85.95% to 32.3%.

Unsteady Numerical Simulation of Two-Dimensional Airflow over a Square Cross-Section at High Reynolds Numbers as a Reduced Model of Wind Actions on Buildings

Airflow over a square cross-section at high Reynolds numbers and different angles of incidence is investigated with the aim of providing deeper insight into wind actions on elongated structures and, in particular, tall buildings. The flow around bluff bodies is characterized by separation at sharp corners, as well as possible flow reattachment at side surfaces. The alternate shedding of vortices is also generated in the wake of bluff bodies due to the unsteady nature of flow separation. Two-dimensional (2D) URANS numerical simulations were conducted in order to model transient flow and examine wind actions on a square used as a model of a typical cross-section of a tall building far from its roof and the ground. For validation purposes, the study’s numerical results on drag and lift coefficients, Strouhal numbers, as well as pressure coefficient distribution were found to be in good agreement with available experimental and numerical results in the literature for relatively low Reynolds numbers. The numerical study was then extended to higher Reynolds numbers, approaching values that are pertinent for wind flow around buildings, thus addressing the lack of such results in the literature. On the basis of these results, the impact of Reynolds numbers and angles of incidence on drag and lift coefficients, as well as the pressure coefficient distribution along the walls of the cross-section, is highlighted.