在紊流流場量測中，一般來說在兩個特點上必須具備較高的反應頻率，一個是在時間上的解析，另一方面則是空間上的解析；而從另一個角度，就量測量測流場速度的方法而言，最常見的可分為侵入型量測法與非侵入型量測法。
於本研究中使用之熱線/熱膜測速儀(HWA/HFA)來做為侵入型量測的代表數據。以其具有於時間解析度高的優勢，除了可以量測一階統計量的紊流特性(x,y 方向平均速度)，也可以量測較為高階之紊流特性，如紊流強度，文末更使用了四階統計量 :峰態係數(Flatness或Kurtosis) 來決定圓柱尾流紊流場的尾流寬度。在熱線測速儀我們使用單熱線探針及交叉陣列熱線探針，熱膜測速儀部分則是使用裂膜探針。
研究中我們針對每種探針本身的能力及校正公式與計算方法去做了解。單熱線探針因其計算而得的結果為速率，使其在二維流場量測會失去其所代表之物理意義而失真，單熱線探針只適合量測單純的一維流場，而並不適合量測多維流場。交叉陣列熱線探針有其四分之一量測平面的限制，導致在量測上會有與自身假設產生矛盾的情況，若量測數據中，流向角度大於其量測平面的資料太多會使其失真。裂膜探針吾人利用其在於半平面量測的優勢，除了使用將其裂孔朝向流場主流向的擺置法，可以量測比交叉陣列熱線探針更廣泛的截面之外，嘗試著使用另外一種擺置法將裂孔垂直於流場，利用兩片薄膜的電壓差量測逆向流場，彌補現今侵入型量測於圓柱尾流迴流區的缺點，並討論其在角度內插上的面臨的問題與處理方法。最後總結每種探針的能力及其優缺點後依其特性搭配常態分佈的「68-95-99.7法則」繪出高可信度之熱線/熱膜測速儀資料篩選流程圖以篩選出較可信之實驗結果。
本研究中，除了使用了侵入型量測法量測，並搭配非侵入型流場量測數據 (PIV) 做比較與討論，藉由比較這兩種方法的量測結果，建立起高可信度之圓柱尾流紊流場的數據庫，並搭配峰態係數找出的尾流寬度，利用迴流區長度作為特徵長度，繪出在兩個雷諾數 〖Re〗_d = 3856, 9959下的圓柱尾流流場適用量測區域圖，讓日後的人可以在量測前先評估此處用何種儀器較為恰當與準確。

There are two different analyses for turbulent flow quantities, namely, temporal and spatial correlations. Two-dimensional velocity information of the turbulent flow over an axisymmetric cylinder in a downward vertical wind tunnel will be measured using both the cross-type hot-wire and the split-type hot-film anemometry as well as the particle image velocimetry (PIV) in this study. The hot-wire and hot-film anemometry are of intrusive, point-wise velocity anemometry and are capable of measuring the temporal velocity information. In contrast, the PIV is of non-intrusive, planar velocity anemometry and is capable of measuring the spatial velocity information. Comparison of the measured turbulent flow quantities over the cylinder among these three velocity anemometry will be made. Determination of the wake width can be accurately made by means of the sectional distribution of either flatness factor on shear-induced vorticity. The flatness factor is a fourth-order temporal statistics of turbulence and will be calculated using the data measured with the cross-type hot-wire anemometry, while the shear-induced vorticity is regarded with the spatial derivatives of velocity and will be calculated using the data measured with the PIV. Finally, the merits and defects of the employed three velocity anemometry on the measurements of turbulent flow quantities will be discussed.

[1] Arie, M., Kiya,M., Susuki, Y., Hagino, M., Takahashi, K. (1981). “ Characteristics of circular cylinders in turbulent flows”. Japan Society of Mechanical Engineers. 24, pp. 532- 582.
[2] Barlow, Jewel B. (1999). Low-speed wind tunnel testing. New york, John Wiley & Sons.
[3] Bloor, M. S. (1964). “ The transition to turbulence in the wake of a circular cylinder”. Journal of Fluid Mechanics. 19(2), pp 290- 304.
[4] Bloor, M. S. , Gerrard, J. H. (1966). “ Measurements on Turbulent Vortices in a Cylinder Wake”. Mathematical and Physical Sciences. 294, pp. 319-342.
[5] Bruun, H. H. (1995). Hot-Wire Anemometry. New york, Oxford university press.
[6] Bruun, H. H., Nabhani, N., Fardad, A. A., & Alkayiem, H. H. (1990). “Velocity component measurements by x-hot-wire anemometry”. Measurement Science & Technology, 1(12), pp. 1314-1321.
[7] Chen, C.J., L.-D.Chen, & F.M. Holly, Jr. (1987). Turbulence measurements and flow modeling. Washington, Hemisphere Pub. Corp.
[8] Cutler, A. D., & Bradshaw, P. (1991). “A crossed hot-wire technique for complex turbulent flows”. Experiments in Fluids, 12(1-2), pp. 17-22.
[9] Fransson, J. H. M., & Westin, K. J. A. (2002). “Errors in hot-wire X-probe measurements induced by unsteady velocity gradients” Experiments in Fluids, 32(3), pp. 413-415.
[10] Freymuth, P. (1968). “Noise in hot-wire anemometers” Review of Scientific Instruments, 39(4), pp. 550-557.
[11] Freymuth, P. (1977). “Frequency-response and electronic testing for constant-temperature hot-wire anemometers” Journal of Physics E-Scientific Instruments, 10(7), pp. 705-710.
[12] Freymuth, P., & Fingerson, L. M. (1997). “Hot-wire anemometry at very high frequencies: Effect of electronic noise” Measurement Science & Technology, 8(2), pp. 115-116.
[13] Gerrard, J. H. (1966). “The mechanics of the formation region of vortices behind bluff bodies”. Journal of Fluid Mechanics. 25(2), pp 401- 413.
[14] Griffin, O.M. (1995) .“A note on bluff body vortex formation” Journal of Fluid Mechanics. 284(2), pp 217- 224.
[15] Heenan, A. F., & Morrison, J. F. (1998). “Split-film probes in recirculating flow” Measurement Science & Technology, 9(4), pp. 638-649.
[16] Hirota, M., Fujita, H., & Yokosawa, H. (1988). “Influences of velocity-gradient on hot-wire anemometry with an x-wire probe” Journal of Physics E-Scientific Instruments, 21(11), pp. 1077-1084.
[17] Jorgensen, F. E. (1971). “Directional sensitivity of wire and fibre-film probes” DISA Info., 11, pp. 31-37.
[18] Jorgensen, F. E., & Hammer, M. (1997). “Hot-wire anemometry behaviour at very high frequencies” Measurement Science & Technology, 8(3), pp. 221-221.
[19] Kunkel, G. J., & Marusic, I. (2003). “An approximate amplitude attenuation correction for hot-film shear stress sensors” Experiments in Fluids, 34(2), pp. 285-290.
[20] Konstantinidis, E., Balabani, S., Yianneskis, M. (2003). “The effect of flow perturbations on the near wake characteristics of a circular cylinder” Journal of Fluids and Structure. 18, pp 367- 386.
[21] Ligrani, P. M., & Bradshaw, P. (1987). “Spatial-resolution and measurement of turbulence in the viscous sublayer using subminiature hot-wire probes” Experiments in Fluids, 5(6), pp. 407-417.
[22] Ljus, C., Johansson, B., & Almstedt, A. E. (2000). “Frequency response correction of hot-film measurements in a turbulent airflow” Experiments in Fluids, 29(1), pp. 36-41.
[23] Lomas, Charles G. (1986). Fundamentals of hot wire anemometry. New York: Cambridge University Press.
[24] Muller, U. R. (1992). “Comparison of turbulence measurements with single, x-wire and triple-hot-wire probes” Experiments in Fluids, 13(2-3), pp. 208-216.
[25] Perry, A. E. (1982). Hot-wire Anemometry. Clarendon Press, Oxford.
[26] Philippe, P., Johan, C., Dominique, H., & Eric, L. (2008). “Experimental and numerical studies of the flow over a circular cylinder at Reynolds number 3900” Physics of Fluids, 20, 085101
[27] Ra, S. H., Chang, P. K., &Park, S. O. (1990). “A modified calibration technique for the split film sensor” Measurement Science & Technology, 1, pp. 1156-1161.
[28] Saddoughi, S. G., & Veeravalli, S. V. (1996). “Hot-wire anemometry behaviour at very high frequencies” Measurement Science & Technology, 7(10), pp. 1297-1300.
[29] Sahin, B., Ozturk, N. A., (2009) “Behaviour of flow at the junction of cylinder and base plate in deep water”. Measurement. 24, pp. 225- 240.
[30] Talamelli, A., Westin, K. J. A., & Alfredsson, P. H. (2000). “An experimental investigation of the response of hot-wire X-probes in shear flows” Experiments in Fluids, 28(5), pp. 425-435.
[31] Uberoi, M. S., & Freymuth, P. (1969). “Spectra of turbulence in wakes behind circular cylinders” Physics of Fluids, 12(7), pp. 1359-1363.
[32] Vukoslavcevic, P. V., Beratlis, N., Balaras, E., Wallace, J. M., & Sun, O. (2009). “On the spatial resolution of velocity and velocity gradient-based turbulence statistics measured with multi-sensor hot-wire probes” Experiments in Fluids, 46(1), pp. 109-119.
[33] Vukoslavcevic, P., & Wallace, J. M. (1981). “Influence of velocity-gradients on measurements of velocity and streamwise vorticity with hot-wire x-array probes” Review of Scientific Instruments, 52(6), pp. 869-879.
[34] Yoshie, R., Tanaka, H., &Shirasawa, T. (2007). “Technique For Simultaneously Measuring Fluctuating Velocity, Temperature And Concentration In Non-Isothermal Flow” ISME.
[35] Zdravkovich, M. M. (1997). Flow Around Circular Cylinders (Vol. 1). New york, Oxford university press.
[36] Zhu, Y., & Antonia, R. A. (1996). “The spatial resolution of hot-wire arrays for the measurement of small-scale turbulence” Measurement Science & Technology, 7(10), pp. 1349-1359.