The predominant effect of stroke length on velocity profiles at the exit of axisymmetric synthetic jet actuators

Kordík, Jozef; Trávníček, Z.; Timchenko, Victoria; Ismail, Nur Atirah

doi:10.1016/j.ijheatfluidflow.2017.06.004

Cited by 9 publications

(4 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Velocity is one of the basic parameters used to calculate almost all parameters inves tigated in SJs [28]. Kordick et al [29] showed that centerline velocity is the representative value in the case of axisymmetric SJs. For this reason, only the centerline velocity of SJs is measured in this paper.…”

Section: Data Reductionmentioning

confidence: 99%

Acoustic and Flow Aspects of Synthetic Jet Actuators with Chevron Orifices

Smyk

Markowicz

2021

Applied Sciences

View full text Add to dashboard Cite

The use of a chevron nozzle/orifice is one of the methods of heat transfer enhancement and noise reduction. In the case of synthetic jets, the number of papers on this topic is small. Therefore, a synthetic jet actuator with three different chevron orifices and one circular orifice is investigated. The aim of this study is to find the impact of orifice shape on centerline velocity (measured with a hot-wire anemometer) and determine if the chevron orifice reduces the generated noise. The sound pressure level was strongly dependent on the input actuator’s power, and only one chevron orifice ensured noise reduction for low power (p = 6; 8 W). At real power p = 12 W, the sound pressure level was lower for each chevron orifice actuator than in the case of the circular orifice actuator. It is shown that the application of a chevron nozzle does not have to provide noise reduction. It is important in the case of the design of new actuators that are to operate in places where noise levels should be limited (e.g., offices).

show abstract

Section: Data Reductionmentioning

confidence: 99%

Acoustic and Flow Aspects of Synthetic Jet Actuators with Chevron Orifices

Smyk

Markowicz

2021

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…This parameter is used as a formation criterion of SJ. It must be noted, that in this case the equivalent diameter was used [40], the hydraulic diameter [41], or another parameter e.g., slot width [5,42]. The formation criterion was fulfilled in the whole measuring range.…”

Section: Time-mean Reaction Force Measurementsmentioning

confidence: 99%

“…This confirms the correctness and compatibility of the methods used because these values are directly proportional to each other-Figure 3 has been drawn from a time-mean force measurement and Figure 6 from hot-wire velocity measurement. Additionally, note that the velocity measured at the center of the cross-section area is representative and can be used to calculate the mean velocity value [40,46].…”

Section: The Centerline Velocity Measurementsmentioning

confidence: 99%

Synthetic Jet Actuators with the Same Cross-Sectional Area Orifices-Flow and Acoustic Aspects

2021

View full text Add to dashboard Cite

In this paper, synthetic jet actuators (SJAs) with three different orifice shapes (circular, square, and slot) with the same cross-section area were investigated. The SJA efficiency and the synthetic jet (SJ) Reynolds number were calculated based on the time-mean reaction force measurement. The momentum velocity was measured with hot-wire anemometry and additionally, the sound pressure level (SPL) was measured. The efficiency was equal maximally to 5.3% for each orifice shape, but the square orifice characterized the higher Reynolds number. The compared centerline (axial) velocities and the radial velocity profile at a distance of 112 mm were similar for each orifice type. The SPL measurement results were surprisingly constant in relation to each other. The square orifice generates the lowest SPL, approximately 2.8dB lower than the circular orifice, and approximately 4.2dB lower than the slot orifice, at each investigated real power. Finally, the differences to other papers and limitations of the approach to comparing orifices presented in the present paper were indicated.

show abstract

“…The first (reference) nozzle was assigned as nozzle A, which was a standard flanged and sharp-edged nozzle with length equal to diameter. From different point of views, such nozzle types were studied within [28][29][30]32,33].…”

mentioning

confidence: 99%

Novel Nozzle Shapes for Synthetic Jet Actuators Intended to Enhance Jet Momentum Flux

Kordík

Trávníček

2018

Actuators

Self Cite

View full text Add to dashboard Cite

An axisymmetric synthetic jet actuator based on a loudspeaker and five types of flanged nozzles were experimentally tested and compared. The first (reference) type of nozzle was a common sharp-edged circular hole. The second type had a rounded lip on the inside. The third nozzle type was assembled from these two types of nozzles—it had a rounded lip on the inside and straight section on the outside. The fourth nozzle was assembled using orifice plates such that the rounded lips were at both inner and outer nozzle ends. The last nozzle was equipped with an auxiliary nozzle plate placed at a small distance downstream of the main nozzle. The actuators with particular nozzles were tested by direct measurement of the synthetic jet (SJ) time-mean thrust using precision scales. Velocity profiles at the actuator nozzle exit were measured by a hot-wire anemometer. Experiments were performed at eight power levels and at the actuator resonance frequency. The highest momentum flux was achieved by the nozzle equipped with an auxiliary nozzle plate. Namely, an enhancement was approximately 31% in comparison with an effect of the reference nozzle at the same input power. Furthermore, based on the cavity pressure and the experimental velocity profiles, parameters for a lumped element model (mass of moving fluid and pressure loss coefficient) were evaluated. These values were studied as functions of the dimensionless stroke length.

show abstract

The predominant effect of stroke length on velocity profiles at the exit of axisymmetric synthetic jet actuators

Cited by 9 publications

References 53 publications

Acoustic and Flow Aspects of Synthetic Jet Actuators with Chevron Orifices

Acoustic and Flow Aspects of Synthetic Jet Actuators with Chevron Orifices

Synthetic Jet Actuators with the Same Cross-Sectional Area Orifices-Flow and Acoustic Aspects

Novel Nozzle Shapes for Synthetic Jet Actuators Intended to Enhance Jet Momentum Flux

Contact Info

Product

Resources

About