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A Nozzle is a mechanical device that uses pressure energy and fluid enthalpy to increase the outflow velocity and control fluid flow direction. To obtain the nozzle duct's shock pattern, the flow inside the nozzle must be supersonic with a Mach number greater than one. Experimentally, the shock pattern is obtained for a nozzle with a Mach number 2 and nozzle pressure ratio (NPR) equivalent to 7 and below. For Mach M = 2, the needed NPR is equal to 7.82 for correct expansion.. When the NPR is greater than 7.82, flow from the nozzles is under-expanded. For NPR less than 7.72 the flow from the nozzle is over-expanded. In this paper, the computational fluid mechanics (CFD) technique was used to simulate the nozzle flow based on the experimental investigation. A two-dimensional transient compressible flow of air through a supersonic nozzle was simulated using ANSYS fluent software. A time-dependent flow using the density-based implicit solver was useds to analyze the simulation results. The results illustrate that the CFD technique simulates the fluid flows and the formation of shock in a duct and gives useful information about fluid dynamics analysis.

Complex terrain can influence wind turbine wakes and wind speed profiles in a wind farm. Consequently, predicting the performance of wind turbines and energy production over complex terrain is more difficult than it is over flat terrain. In this preliminary study, an engineering wake model, that considers acceleration on a two-dimensional hill, was developed based on the momentum theory. The model consists of the wake width and wake wind speed. The equation to calculate the rotor thrust, which is calculated by the wake wind speed profiles, was also formulated. Then, a wind-tunnel test was performed in simple flow conditions in order to investigate wake development over a two-dimensional hill. After this the wake model was compared with the wind-tunnel test, and the results obtained by using the new wake model were close to the wind-tunnel test results. Using the new wake model, it was possible to estimate the wake shrinkage in an accelerating two-dimensional wind field.

Background: Vocal cords signify an imperative lane for air flow in and out of the respiratory tract along with a phonetic role. So, the aim of this work is to assess the impact of habitual versus occasional utilization of inhalation therapy of patients with bronchial asthma on their vocal cords regarding visual endoscopic pathological changes in addition to phonetic dysfunction. This study was conducted on 112 diagnosed bronchial asthma patients (66 male and 46 females). They were classified into the following: group A (habitual user), 65 patients with severe persistent asthma with regular frequent intake of inhalation therapy, and group B (occasional user), 47 patients with intermittent asthma with alternating intake of inhalation therapy. They were submitted to clinical, vocal assessment plus laryngoscopic examination. Results: The habitual users group demonstrated that laryngeal edema and hyperemia attained the higher percentage in the adult than children age group (60%, 40-67.3%, 50%) respectively together after 6 and 9 months of study followed by laryngeal nodules (5.4%, 0-9%, 10%). Occasional users presented the same findings comparable to the habitual group (27%, 10-32.4%, 20%). Cord paresis, cord dysfunction, and fungal plaques were in the second frequencies in both age groups with the same percentage (3.6%) at the end of the study; however, in occasional users, fungal plaques illustrated low percentage (2.7%, 5.4-0, 10%, respectively). Conclusion: Inhalation therapy as a form of asthma medication correlated with major counter effects on vocal cords with well-recorded laryngeal hyperemia, edema, and vocal nodules in addition to fungal plaques moreover phonetic dysfunction.