Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface she...Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface shear stress measurement technique de-termined by Reda et al. to wind tunnel studies. All the facilities employed in the technique are very common and simple. The measurement technique is applied to surface flow beneath a tangential jet and surface flow in a turbulence wedge generated by a small cylinder in windtunnel flow. Spatially resolved shear stresses over planar surface are obtained, although the magnitude is not fully calibrated.展开更多
In this paper, a novel liquid refractive index （R/） sensor based on fused tapered photonic crystal fiber （PCF） is proposed. It is fabricated by fusing and tapering a section of PCF which is spliced with two single...In this paper, a novel liquid refractive index （R/） sensor based on fused tapered photonic crystal fiber （PCF） is proposed. It is fabricated by fusing and tapering a section of PCF which is spliced with two single-mode fibers （SMFs）. Due to the fused biconical taper method, the sensor becomes longer and thinner, to make the change of the outside RI has more direct effects on the internal optical field of the PCF, which finally enhances the sensitivity of this sensor. Experimental results show that the transmission spectra of the sensor are red-shifted obviously with the increase of RI. The longer the tapered region of the sensor, the higher the sensitivity is. This sensor has the advantages of simple structure, easy fabri- cation, high performance and so on, so it has potential applications in RI measurement.展开更多
基金supported by the Doctorate Creation Foundation of North-western Polytechnical University (Grant No. CX200902)
文摘Shear sensitive liquid crystal coating (SSLCC) can measure surface shear stress vector distribution efficiently with a high spa-tial resolution. The purpose of the present paper is to modify and extend the surface shear stress measurement technique de-termined by Reda et al. to wind tunnel studies. All the facilities employed in the technique are very common and simple. The measurement technique is applied to surface flow beneath a tangential jet and surface flow in a turbulence wedge generated by a small cylinder in windtunnel flow. Spatially resolved shear stresses over planar surface are obtained, although the magnitude is not fully calibrated.
基金supported by the National Natural Science Foundation of China(Nos.6120506861475133 and 61575170)+4 种基金the College Youth Talent Project of Hebei Province(No.BJ2014057)the Hebei Provincial Natural Science Foundation(No.F2015203270)the Hebei Provincial Science and Technology Program(Nos.15273304D and 14273301D)the"XinRuiGongCheng"Talent Projectthe Excellent Youth Funds for School of Information Science and Engineering in Yanshan University(No.2014201)
文摘In this paper, a novel liquid refractive index （R/） sensor based on fused tapered photonic crystal fiber （PCF） is proposed. It is fabricated by fusing and tapering a section of PCF which is spliced with two single-mode fibers （SMFs）. Due to the fused biconical taper method, the sensor becomes longer and thinner, to make the change of the outside RI has more direct effects on the internal optical field of the PCF, which finally enhances the sensitivity of this sensor. Experimental results show that the transmission spectra of the sensor are red-shifted obviously with the increase of RI. The longer the tapered region of the sensor, the higher the sensitivity is. This sensor has the advantages of simple structure, easy fabri- cation, high performance and so on, so it has potential applications in RI measurement.
