@article{manning_chokani_2004, title={Computational evaluation of quiet tunnel hypersonic boundary-layer stability experiments}, volume={41}, ISSN={["1533-6794"]}, DOI={10.2514/1.10698}, abstractNote={Abstract : A computational evaluation of two stability experiments conducted in the NASA Langley Mach 6 axisymmetric quiet nozzle test chamber facility is conducted. Navier- Stokes analysis of the mean flow and linear stability theory analysis of boundary layer disturbances is performed in the computations. The effects of adverse pressure gradient and wall cooling are examined. Calculated pressure, temperature and boundary layer thickness distributions show very good overall agreement with experimental measurements. Computed mass flux and total temperature profiles show very good quantitative agreement with uncalibrated hot- wire measurements obtained with the hot-wire operated in high and low overheat modes respectively. Comparisons between calibrated hot-wire data and mean flow computations show excellent agreement in the early stages of the transitional flow. However, examination of the wire Reynolds number and mass flux and total temperature eigenfunction profiles suggest that when operated in high overheat mode the sensitivity of the hot-wire to total temperature is significant. Thus, while uncalibrated hot-wire measurements are useful to characterize the overall features of the flow, calibrated hot- wire measurements are necessary for quantitative comparison with stability theory. Computations show that adverse pressure gradient and wall cooling decrease the boundary layer thickness and increase the frequency and amplification rate of the unstable second mode disturbances; these findings are consistent with the experimental observations.}, number={3}, journal={JOURNAL OF SPACECRAFT AND ROCKETS}, author={Manning, ML and Chokani, N}, year={2004}, pages={406–415} }
 @article{truzzi_sarma_chokani_2002, title={Constant voltage anemometer operated hot wire at subsonic speeds over wide overheats in unsteady flows}, volume={73}, ISSN={["0034-6748"]}, DOI={10.1063/1.1516850}, abstractNote={The constant voltage anemometer (CVA) was used to calibrate a hot wire over a wide overheat range. Instead of the output voltage (E) of the anemometer which is normally used, at each test point a quantity represented by “pdr” equal to the ratio of power dissipated in the hot wire (Pw) and the associated difference in the heated resistance of the hot wire (Rw) and its resistance (Ra) at the ambient fluid temperature is calculated. It is shown that the calibration curves so obtained with pdr=Pw/(Rw−Ra) as the output variable instead of E can be represented by a single calibration equation covering the wide overheat range. Overheat variation is equivalent to allowing an ambient temperature change of the fluid at a given setting. It demonstrates that this approach can be used to cover measurements using the hot wire with fluid temperature drifts without using a second hot wire for temperature corrections and without any temperature calibration. The calibration data was then applied to measure the unsteady flow in the near orifice region of synthetic jets with very good results. The measurements confirm the computational predictions that show that although there is flow reversal, over a cycle of oscillation, the synthetic jet actuator spends most of the cycle ejecting rather than ingesting fluid.}, number={12}, journal={REVIEW OF SCIENTIFIC INSTRUMENTS}, author={Truzzi, GE and Sarma, GR and Chokani, N}, year={2002}, month={Dec}, pages={4363–4368} }
 @article{chokani_1999, title={Nonlinear spectral dynamics of hypersonic laminar boundary layer flow}, volume={11}, number={12}, journal={Physics of Fluids (Woodbury, N.Y.)}, author={Chokani, N.}, year={1999}, pages={3846–3851} }
 @article{lamp_chokani_1997, title={Computation of cavity flows with suppression using jet blowing}, volume={34}, ISSN={["0021-8669"]}, DOI={10.2514/2.2207}, abstractNote={A computational investigation of a compressible cavity e ow was conducted. Blowing was implemented to suppress the large pressure oscillations characteristic of cavity e ows. The cavity length-to-depth ratio was 4.33, and the freestream Mach number was 1.75. A two-dimensional, time-accurate Navier› Stokes scheme was used to simulate the e ow. A small jet placed within the cavity just below the front lip was used to force the shear layer with different amplitudes and frequencies. This control technique was successful in reducing the amplitude of the oscillations. Furthermore, the effectiveness of the control was found to depend upon the jet frequency, amplitude, phase angle, and duty cycle. Autocorrelation analysis showed that the jet decreased the size of the structures in the shear layer. Cross-correlation analysis showed that the timing of events within the cavity were unaffected by the jet blowing.}, number={4}, journal={JOURNAL OF AIRCRAFT}, author={Lamp, AM and Chokani, N}, year={1997}, pages={545–551} }
 @article{hudson_chokani_candler_1997, title={Linear stability of hypersonic flow in thermochemical nonequilibrium}, volume={35}, ISSN={["0001-1452"]}, DOI={10.2514/2.204}, abstractNote={Foright at high Mach numbers, thermal and chemical nonequilibrium may exist in the meanow and thus affectthestabilityoftheow.Acomputationaltoolwasdevelopedtoanalyzeahypersonicmeanowanditsstability including thermochemical nonequilibrium. The meanow analysis employs the Navier± Stokes equations with a translational/vibrational temperature model for thermal nonequilibrium and a ® ve-species reacting air model for chemicalnonequilibrium. Thestability analysisemployslinearstability theory to describethespatialampli® cation of two- and three-dimensionaldisturbances. Thecomputational tool is used to determinethe frequency and spatial ampli® cation of disturbances that may lead to boundary layertransition on cold wall and adiabaticat plates. The effect of thermal and chemical nonequilibrium on stability is shown to depend on the disturbance mode.}, number={6}, journal={AIAA JOURNAL}, author={Hudson, ML and Chokani, N and Candler, GV}, year={1997}, month={Jun}, pages={958–964} }