In this paper, six different shape obstacles, namely, Isosceles trapezoid (Type 1), Triangular with curve apex (Type 2), Rectangular with chamfered edges (Type 3), Rectangular with curve edges (Type 4), Triangular with curve corner at bottom (Type 5) and Triangular shape (Type 6) have been tested in inline and staggered fashions in solar air heater (SAH) duct. This work aims to investigate the effect of obstacle shape on heat transfer and friction characteristics. All experiments have been carried out at eight different values of Reynolds number ranging from 2000 to 16000 and fixed value of heat flux of 1000 W/m². As results, Nusselt number and friction factor characteristics have been presented and discussed. The maximum enhancement in Nusselt number and friction factor are observed in case isosceles trapezoid obstacles (Type 1) and rectangular with curve edges obstacles (Type 4) when mounted in staggered fashion, respectively and their respective average enhancement factor in Nusselt number and friction factor are observed as 2.95 and 4.37. Also, thermo-hydraulic performance parameter (η) of all obstacles in both arrangement have been evaluated and found to be average maximum values 1.88 in case of isosceles trapezoid obstacles (Type 1) in staggered manner.

The present experimental and simulation investigation includes aerodynamic drag reduction over a car by flow control using a vortex generator (VG) and spoiler. The model of the car was fabricated on the scale of 15:1 using plaster of Paris. A test facility is built to convincingly replicate the flow over a model of a high-speed car. Primarily, the car model is tested at different incidence angles of flow to obtain total drag over the model. Furthermore, 26 different combinations were tested to find out the condition for minimum drag. In the crosswind condition (± 30 deg), 36.36% additional area of the car is exposed to the direct wind that causes an increment of 38.61% in the drag coefficient. The increment of flow angle from 0 to 30 deg causes flow separation on the roof of the vehicle near the leeward corner. The maximum 68.18% drag coefficient is reduced at β = 0 deg, α = +45 deg, and the co-rotating VG. The best combination in terms of a surface static pressure coefficient rise (from -0.041 to +2.622) is found at β = 0 deg, α = 0 deg, and the VG attached to the upstream of the spoiler. A formulated computational fluid dynamics model is in good match with the experimental results.

The present experimental investigation includes finding the variation of drag coefficient, wall static pressures, and aerodynamic drag over a vehicle for twenty-six different orientations of vehicle. The flow was controlled using the submerged type vortex generator (VG) in combination with the rear spoiler during the investigation. The model of a vehicle was fabricated on the reducing scale (15:1) using the Plaster of Paris (PoP). Primarily, the vehicle was tested at the different incidence yaw angles to obtain the totaldrag over the model. Further, twenty-six different combinations obtained by changing the flow angles (β = 0 and ±30°), spoiler angles (α =0 and ±45°) and orientations of VGs were tested. A variation of static pressures and drag coefficients for all combinations was analyzed. Further, the development of secondary-flow was also traced. Secondary flow becomes important as it causes a sheared flow produced near the body and wall of a sadden vehicle which further deflects the air pressure on the roof of the vehicle body. The variation of the secondary flow was obtained with the wall static pressure, surface static pressure and boundary layer by changing the flow angles ( β = 0 and ±30°), and spoiler angles (α =0 and ±45°) and orientations of VGs. The best combination in terms of surface static pressure coefficient (Cwp) rise (from –0.041 to +2.622) is found at β = 0°, α = 0° and the VG attached to the upstream of the spoiler. CFD analysis is conducted using ANSYS FLUENT® and Solid Works was used for building the geometries of the car andspoiler. A formulated computational fluid dynamics model is in good match with the experimental results.

The use of laminated glass (LG) is growing in structural applications. The conventional methods used to cut LG involve cutting glasses and interlayer separately and, thus, are less productive. The present work reports the use of abrasive water jet machining (AWJM) for LG cutting for the first time in the open literature. The statistical methods have determined the optimum process parameters of AWJM for the LG cutting. The boundaries of LG sample cut using conventional method and AWJM are examined using atomic force microscopy (AFM). Three-point bending tests have highlighted the superiority in the load-bearing ability and fracture pattern for LG samples cut by AWJM. A finite element (FE) model formed using an explicit dynamic module of ANSYS has explored the experimental findings. The FE model has predicted the stresses and strain for the glass and polyvinyl butyral (PVB) interlayer due to the strike of single SiC abrasive particles. The findings should be useful for the practical guidance to both the academic community and industry.