The phrase "at the upper wall" is correct and usable in written English.
It can be used to describe a location or position that is situated on or near the top part of a wall.
Example: "The painting was hung at the upper wall of the gallery, drawing attention from all visitors."
Alternatives: "on the top wall" or "at the top of the wall".
T c temperature at the upper wall.
However, for the sections where dipoles are close to the upper wall (i.e., dipoles 2 and 4), the increase in the convective heat transfer is greater at the upper wall.
The temperatures at the lower and upper wall are T 1 and T 0 with T 1 > T 0. The nanoparticle volume fractions are ϕ 0 at the lower wall and ϕ 1 at the upper wall, and it is assumed that the difference ϕ 1 − ϕ 0 is small in comparison with ϕ 0. A uniform magnetic field of strength B is imposed normal to the plate.
At this level, the maximum allowable void fraction has been exceeded indicating that gas bubbles have attained their saturation limit at the upper wall.
Physically, this can be explained by the upward migration of gas bubbles due to the upward buoyant force balancing with the downward wall lubrication force to prevent the gas bubbles from collapsing at the upper wall.
Equations 17 and 18 then lead to the following boundary conditions for the perturbation quantities for the case when both the lower and upper walls are rigid: w ′ = 0, ∂ w ′ ∂ z = 0, T ′ = 0, ϕ ′ = 0, d n ′ d z = 0, d C ′ d z = 0 at z = 1 ( the lower wall ) (37) w ′ = 0, ∂ w ′ ∂ z = 0, T ′ = 0, ϕ ′ = 0, P e [ n b d C ′ d z + d C b d z n ′ ] − d n ′ d z = 0, C ′ = 0 at z = 0 ( the upper wall ) (38).
The hard stochastic wall model introduces a system energy leakage which is counteracted by elevating the upper wall temperature by at least 0.16 ND temperature units over the lower cold wall temperature.
Torrance et al. [1] investigated the fluid motion in a lid-driven cavity where the upper wall was maintained at a different temperature to that of the other walls in the cavity.
At time:04 [sec], the needle approaches the upper wall of the vein.
Here the upper wall of the channel (at y = d ) is set into oscillatory motion while the lower wall (at y = 0), is held stationary.
At time:04 [sec], the needle has moved while deflecting the upper wall of the vein downward on the screen.
